Add how-to-make-thread-safe-calls.md & Update Layout with margin/padding (#1119)

* Update with margin/padding * add how-to-make-thread-safe-calls * reverse property mentions
2026-09-04 00:56:03 +02:00 · 2021-07-26 18:14:58 -04:00
parent 09d28345c2
commit d30fae457c
35 changed files with 1341 additions and 9 deletions
@@ -1,6 +1,6 @@
 ---
 title: How to add or remove an event handler
-description: Learn how to create an event handler at design-time with the Windows Forms Designer in Visual Studio or at run-time.
+description: Learn how to create an event handler for a control at design-time with the Windows Forms Designer in Visual Studio or at run-time.
 ms.date: 07/16/2021
 dev_langs:
  - "csharp"
@@ -18,7 +18,7 @@ helpviewer_keywords:
  - "menu items [Windows Forms], multicasting event-handling methods"
 ---

-# How to handle an event (Windows Forms .NET)
+# How to handle a control event (Windows Forms .NET)

 Events for controls (and for forms) are generally set through the Visual Studio Visual Designer for Windows Forms. Setting an event through the Visual Designer is known as handling an event at design-time. You can also handle events dynamically in code, known as handling events at run-time. An event created at run-time allows you to connect event handlers dynamically based on what your app is currently doing.

@@ -0,0 +1,64 @@
+---
+title: How to make thread-safe calls to controls
+description: Learn how to implement multithreading in your app by calling cross-thread controls in a thread-safe way. If you encounter the 'cross-thread operation not valid' error, use the InvokeRequired property to detect this error. The BackgroundWorker component is also an alternative to creating new threads.
+ms.date: 06/20/2021
+dev_langs:
+  - "csharp"
+  - "vb"
+f1_keywords: 
+  - "EHInvalidOperation.WinForms.IllegalCrossThreadCall"
+helpviewer_keywords: 
+  - "thread safety [Windows Forms], calling controls [Windows Forms]"
+  - "calling controls [Windows Forms], thread safety [Windows Forms]"
+  - "CheckForIllegalCrossThreadCalls property [Windows Forms]"
+  - "Windows Forms controls [Windows Forms], multithreading"
+  - "BackgroundWorker class [Windows Forms], examples"
+  - "threading [Windows Forms], cross-thread calls"
+  - "controls [Windows Forms], multithreading"
+---
+
+# How to make thread-safe calls to controls (Windows Forms .NET)
+
+Multithreading can improve the performance of Windows Forms apps, but access to Windows Forms controls isn't inherently thread-safe. Multithreading can expose your code to serious and complex bugs. Two or more threads manipulating a control can force the control into an inconsistent state and lead to race conditions, deadlocks, and freezes or hangs. If you implement multithreading in your app, be sure to call cross-thread controls in a thread-safe way. For more information, see [Managed threading best practices](/dotnet/standard/threading/managed-threading-best-practices).
+
+[!INCLUDE [desktop guide under construction](../../includes/desktop-guide-preview-note.md)]
+
+There are two ways to safely call a Windows Forms control from a thread that didn't create that control. Use the <xref:System.Windows.Forms.Control.Invoke%2A?displayProperty=fullName> method to call a delegate created in the main thread, which in turn calls the control. Or, implement a <xref:System.ComponentModel.BackgroundWorker?displayProperty=nameWithType>, which uses an event-driven model to separate work done in the background thread from reporting on the results.
+
+## Unsafe cross-thread calls
+
+It's unsafe to call a control directly from a thread that didn't create it. The following code snippet illustrates an unsafe call to the <xref:System.Windows.Forms.TextBox?displayProperty=nameWithType> control. The `Button1_Click` event handler creates a new `WriteTextUnsafe` thread, which sets the main thread's <xref:System.Windows.Forms.TextBox.Text%2A?displayProperty=nameWithType> property directly.
+
+:::code language="csharp" source="snippets/how-to-make-thread-safe-calls/cs/FormBad.cs" id="Bad":::
+:::code language="vb" source="snippets/how-to-make-thread-safe-calls/vb/FormBad.vb" id="Bad":::
+
+The Visual Studio debugger detects these unsafe thread calls by raising an <xref:System.InvalidOperationException> with the message, **Cross-thread operation not valid. Control accessed from a thread other than the thread it was created on.** The <xref:System.InvalidOperationException> always occurs for unsafe cross-thread calls during Visual Studio debugging, and may occur at app runtime. You should fix the issue, but you can disable the exception by setting the <xref:System.Windows.Forms.Control.CheckForIllegalCrossThreadCalls%2A?displayProperty=nameWithType> property to `false`.
+
+## Safe cross-thread calls
+
+The following code examples demonstrate two ways to safely call a Windows Forms control from a thread that didn't create it:
+
+1. The <xref:System.Windows.Forms.Control.Invoke%2A?displayProperty=fullName> method, which calls a delegate from the main thread to call the control.
+2. A <xref:System.ComponentModel.BackgroundWorker?displayProperty=nameWithType> component, which offers an event-driven model.
+
+In both examples, the background thread sleeps for one second to simulate work being done in that thread.
+
+## Example: Use the Invoke method
+
+The following example demonstrates a pattern for ensuring thread-safe calls to a Windows Forms control. It queries the <xref:System.Windows.Forms.Control.InvokeRequired%2A?displayProperty=fullName> property, which compares the control's creating thread ID to the calling thread ID. If they're different, you should call the <xref:System.Windows.Forms.Control.Invoke%2A?displayProperty=nameWithType> method.
+
+The `WriteTextSafe` enables setting the <xref:System.Windows.Forms.TextBox> control's <xref:System.Windows.Forms.TextBox.Text%2A> property to a new value. The method queries <xref:System.Windows.Forms.Control.InvokeRequired%2A>. If <xref:System.Windows.Forms.Control.InvokeRequired%2A> returns `true`, `WriteTextSafe` recursively calls itself, passing the method as a delegate to the <xref:System.Windows.Forms.Control.Invoke%2A> method. If <xref:System.Windows.Forms.Control.InvokeRequired%2A> returns `false`, `WriteTextSafe` sets the <xref:System.Windows.Forms.TextBox.Text%2A?displayProperty=nameWithType> directly. The `Button1_Click` event handler creates the new thread and runs the `WriteTextSafe` method.
+
+:::code language="csharp" source="snippets/how-to-make-thread-safe-calls/cs/FormThread.cs" id="Good":::
+:::code language="vb" source="snippets/how-to-make-thread-safe-calls/vb/FormThread.vb" id="Good":::
+
+## Example: Use a BackgroundWorker
+
+An easy way to implement multithreading is with the <xref:System.ComponentModel.BackgroundWorker?displayProperty=nameWithType> component, which uses an event-driven model. The background thread raises the <xref:System.ComponentModel.BackgroundWorker.DoWork?displayProperty=nameWithType> event, which doesn't interact with the main thread. The main thread runs the <xref:System.ComponentModel.BackgroundWorker.ProgressChanged?displayProperty=nameWithType> and <xref:System.ComponentModel.BackgroundWorker.RunWorkerCompleted?displayProperty=nameWithType> event handlers, which can call the main thread's controls.
+
+To make a thread-safe call by using <xref:System.ComponentModel.BackgroundWorker>, handle the <xref:System.ComponentModel.BackgroundWorker.DoWork> event. There are two events the background worker uses to report status: <xref:System.ComponentModel.BackgroundWorker.ProgressChanged> and <xref:System.ComponentModel.BackgroundWorker.RunWorkerCompleted>. The `ProgressChanged` event is used to communicate status updates to the main thread, and the `RunWorkerCompleted` event is used to signal that the background worker has completed its work. To start the background thread, call <xref:System.ComponentModel.BackgroundWorker.RunWorkerAsync%2A?displayProperty=nameWithType>.
+
+The example counts from 0 to 10 in the `DoWork` event, pausing for one second between counts. It uses the <xref:System.ComponentModel.BackgroundWorker.ProgressChanged> event handler to report the number back to the main thread and set the <xref:System.Windows.Forms.TextBox> control's <xref:System.Windows.Forms.TextBox.Text%2A> property. For the <xref:System.ComponentModel.BackgroundWorker.ProgressChanged> event to work, the <xref:System.ComponentModel.BackgroundWorker.WorkerReportsProgress%2A?displayProperty=nameWithType> property must be set to `true`.
+
+:::code language="csharp" source="snippets/how-to-make-thread-safe-calls/cs/FormBackgroundWorker.cs" id="Background":::
+:::code language="vb" source="snippets/how-to-make-thread-safe-calls/vb/FormBackgroundWorker.vb" id="Background":::
@@ -1,7 +1,7 @@
 ---
 title: Control layout options
 description: Learn about the different settings on a control that affect layout and positioning in Windows Forms for .NET. Learn about the different types of control containers that affect layout.
-ms.date: 10/26/2020
+ms.date: 07/19/2021
 ms.topic: overview
 helpviewer_keywords: 
  - "forms [Windows Forms], aligning controls"
@@ -36,6 +36,22 @@ When a control is added to a parent that enforces automatic placement, the posit

 The <xref:System.Windows.Forms.Control.MaximumSize%2A> and <xref:System.Windows.Forms.Control.MinimumSize%2A> properties help set the minimum and maximum space a control can use.

+## Margin and Padding
+
+There are two control properties that help with precise placement of controls: <xref:System.Windows.Forms.Control.Margin%2A> and <xref:System.Windows.Forms.Control.Padding%2A>.
+
+The <xref:System.Windows.Forms.Control.Margin%2A> property defines the space around the control that keeps other controls a specified distance from the control's borders.
+
+The <xref:System.Windows.Forms.Control.Padding%2A> property defines the space in the interior of a control that keeps the control's content (for example, the value of its <xref:System.Windows.Forms.Control.Text%2A> property) a specified distance from the control's borders.
+
+The following figure shows the <xref:System.Windows.Forms.Control.Margin%2A> and <xref:System.Windows.Forms.Control.Padding%2A> properties on a control.
+
+:::image type="content" source="media/layout/margin-padding.png" alt-text="Padding and Margin properties for Windows Forms Controls":::
+
+The Visual Studio Designer will respect these properties when you're positioning and resizing controls. Snaplines appear as guides to help you remain outside the specified margin of a control. For example, Visual Studio displays the snapline when you drag a control next to another control:
+
+:::image type="content" source="media/layout/margins.gif" alt-text="Animated image demonstrating the snaplines with margin properties for Windows Forms .NET in Visual Studio":::
+
 ## Automatic placement and size

 Controls can be automatically placed within their parent. Some parent containers force placement while others respect control settings that guide placement. There are two properties on a control that help automatic placement and size within a parent: <xref:System.Windows.Forms.Control.Dock%2A> and <xref:System.Windows.Forms.Control.Anchor>.
@@ -1,7 +1,7 @@
 ---
 title: "Overview of Using Controls"
 description: Learn about how controls are used in Windows Forms for .NET. Controls are reusable components that provide functionality to the user. Many ready-to-use controls are provided. You can also make new controls.
-ms.date: 10/26/2020
+ms.date: 07/21/2021
 ms.topic: overview
 dev_langs: 
  - "csharp"
@@ -27,15 +27,28 @@ The position a control appears on a parent is determined by the value of the <xr

 Besides manual positioning and sizing, various container controls are provided that help with automatic placement of controls.

-For more information, see [Position and layout of controls](layout.md).
-<!-- TODO
+For more information, see [Position and layout of controls](layout.md) and [How to dock and anchor controls](how-to-dock-and-anchor.md).

 ## Control events

-->
+Controls provide a set of common events through the base class: <xref:System.Windows.Forms.Control>. Not every control responds to every event. For example, the <xref:System.Windows.Forms.Label> control doesn't respond to keyboard input, so the <xref:System.Windows.Forms.Control.PreviewKeyDown?displayProperty=nameWithType> event isn't raised. Most shared events fall under these categories:
+
+- Mouse events
+- Keyboard events
+- Property changed events
+- Other events
+
+For more information, see [Control events](events.md) and [How to handle a control event](how-to-add-an-event-handler.md).
+
+## Control accessibility
+
+Windows Forms has accessibility support for screen readers and voice input utilities for verbal commands. However, you must design your UI with accessibility in mind. Windows Forms controls expose various properties to handle accessibility. For more information about these properties, see [Providing Accessibility Information for Controls](provide-accessibility-information.md).

 ## See also

 - [Position and layout of controls](layout.md)
 - [Label control overview](labels.md)
- [Add a control to a form](how-to-add-to-a-form.md)
+- [Control events](events.md)
+- [Types of custom controls](custom.md)
+- [Painting and drawing on controls](custom-painting-drawing.md)
+- [Providing Accessibility Information for Controls](provide-accessibility-information.md)
@@ -0,0 +1,73 @@
+namespace project
+{
+    partial class Form1
+    {
+        /// <summary>
+        ///  Required designer variable.
+        /// </summary>
+        private System.ComponentModel.IContainer components = null;
+
+        /// <summary>
+        ///  Clean up any resources being used.
+        /// </summary>
+        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing && (components != null))
+            {
+                components.Dispose();
+            }
+            base.Dispose(disposing);
+        }
+
+        #region Windows Form Designer generated code
+
+        /// <summary>
+        ///  Required method for Designer support - do not modify
+        ///  the contents of this method with the code editor.
+        /// </summary>
+        private void InitializeComponent()
+        {
+            this.button1 = new System.Windows.Forms.Button();
+            this.textBox1 = new System.Windows.Forms.TextBox();
+            this.SuspendLayout();
+            // 
+            // button1
+            // 
+            this.button1.Location = new System.Drawing.Point(46, 133);
+            this.button1.Name = "button1";
+            this.button1.Size = new System.Drawing.Size(75, 23);
+            this.button1.TabIndex = 0;
+            this.button1.Text = "button1";
+            this.button1.UseVisualStyleBackColor = true;
+            this.button1.Click += new System.EventHandler(this.button1_Click);
+            // 
+            // textBox1
+            // 
+            this.textBox1.Location = new System.Drawing.Point(30, 37);
+            this.textBox1.Name = "textBox1";
+            this.textBox1.Size = new System.Drawing.Size(333, 23);
+            this.textBox1.TabIndex = 1;
+            // 
+            // Form1
+            // 
+            this.AutoScaleDimensions = new System.Drawing.SizeF(7F, 15F);
+            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
+            this.ClientSize = new System.Drawing.Size(800, 450);
+            this.Controls.Add(this.textBox1);
+            this.Controls.Add(this.button1);
+            this.Name = "Form1";
+            this.Text = "Form1";
+            this.Load += new System.EventHandler(this.Form1_Load);
+            this.ResumeLayout(false);
+            this.PerformLayout();
+
+        }
+
+        #endregion
+
+        private System.Windows.Forms.Button button1;
+        private System.Windows.Forms.TextBox textBox1;
+    }
+}
+
@@ -0,0 +1,48 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Data;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+
+namespace project
+{
+    public partial class Form1 : Form
+    {
+        public Form1()
+        {
+            InitializeComponent();
+        }
+
+        private void Form1_Load(object sender, EventArgs e)
+        {
+
+        }
+
+        private async void button1_Click(object sender, EventArgs e)
+        {
+            //var thread2 = new Thread(new ThreadStart(WriteTextUnsafe));
+            //thread2.Start();
+            await Task.Factory.StartNew(WriteTextUnsafe, new CancellationToken(false), TaskCreationOptions.None, TaskScheduler.FromCurrentSynchronizationContext());
+            await Task.Delay(6000);
+            Action de = delegate { WriteTextSafe(); };
+            textBox1.Invoke(de);
+        }
+
+        private async void WriteTextUnsafe()
+        {
+            textBox1.Text = "This text was set unsafely.";
+            await Task.Delay(4000);
+            textBox1.Text = "This text was set unsafely twice!";
+        }
+
+        private void WriteTextSafe()
+        {
+            textBox1.Text = "This text was set safely.";
+        }
+    }
+}
@@ -0,0 +1,60 @@
+<root>
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+</root>
@@ -0,0 +1,80 @@
+
+namespace project
+{
+    partial class FormBackgroundWorker
+    {
+        /// <summary>
+        /// Required designer variable.
+        /// </summary>
+        private System.ComponentModel.IContainer components = null;
+
+        /// <summary>
+        /// Clean up any resources being used.
+        /// </summary>
+        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing && (components != null))
+            {
+                components.Dispose();
+            }
+            base.Dispose(disposing);
+        }
+
+        #region Windows Form Designer generated code
+
+        /// <summary>
+        /// Required method for Designer support - do not modify
+        /// the contents of this method with the code editor.
+        /// </summary>
+        private void InitializeComponent()
+        {
+            this.button1 = new System.Windows.Forms.Button();
+            this.textBox1 = new System.Windows.Forms.TextBox();
+            this.backgroundWorker1 = new System.ComponentModel.BackgroundWorker();
+            this.SuspendLayout();
+            // 
+            // button1
+            // 
+            this.button1.Location = new System.Drawing.Point(24, 135);
+            this.button1.Name = "button1";
+            this.button1.Size = new System.Drawing.Size(75, 23);
+            this.button1.TabIndex = 0;
+            this.button1.Text = "button1";
+            this.button1.UseVisualStyleBackColor = true;
+            this.button1.Click += new System.EventHandler(this.button1_Click);
+            // 
+            // textBox1
+            // 
+            this.textBox1.Location = new System.Drawing.Point(24, 106);
+            this.textBox1.Name = "textBox1";
+            this.textBox1.Size = new System.Drawing.Size(236, 23);
+            this.textBox1.TabIndex = 1;
+            // 
+            // backgroundWorker1
+            // 
+            this.backgroundWorker1.WorkerReportsProgress = true;
+            this.backgroundWorker1.DoWork += new System.ComponentModel.DoWorkEventHandler(this.backgroundWorker1_DoWork);
+            this.backgroundWorker1.ProgressChanged += new System.ComponentModel.ProgressChangedEventHandler(this.backgroundWorker1_ProgressChanged);
+            // 
+            // FormBackgroundWorker
+            // 
+            this.AutoScaleDimensions = new System.Drawing.SizeF(7F, 15F);
+            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
+            this.ClientSize = new System.Drawing.Size(800, 450);
+            this.Controls.Add(this.textBox1);
+            this.Controls.Add(this.button1);
+            this.Name = "FormBackgroundWorker";
+            this.Text = "FormBackgroundWorker";
+            this.ResumeLayout(false);
+            this.PerformLayout();
+
+        }
+
+        #endregion
+
+        private System.Windows.Forms.Button button1;
+        private System.Windows.Forms.TextBox textBox1;
+        private System.ComponentModel.BackgroundWorker backgroundWorker1;
+    }
+}
@@ -0,0 +1,44 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Data;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+
+namespace project
+{
+    public partial class FormBackgroundWorker : Form
+    {
+        public FormBackgroundWorker()
+        {
+            InitializeComponent();
+        }
+
+        //<Background>
+        private void button1_Click(object sender, EventArgs e)
+        {
+            if (!backgroundWorker1.IsBusy)
+                backgroundWorker1.RunWorkerAsync();
+        }
+
+        private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
+        {
+            int counter = 0;
+            int max = 10;
+
+            while (counter <= max)
+            {
+                backgroundWorker1.ReportProgress(0, counter.ToString());
+                System.Threading.Thread.Sleep(1000);
+                counter++;
+            }
+        }
+
+        private void backgroundWorker1_ProgressChanged(object sender, ProgressChangedEventArgs e) =>
+            textBox1.Text = (string)e.UserState;
+        //</Background>
+    }
+}
@@ -0,0 +1,63 @@
+<root>
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <metadata name="backgroundWorker1.TrayLocation" type="System.Drawing.Point, System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+    <value>17, 17</value>
+  </metadata>
+</root>
@@ -0,0 +1,72 @@
+
+namespace project
+{
+    partial class FormBad
+    {
+        /// <summary>
+        /// Required designer variable.
+        /// </summary>
+        private System.ComponentModel.IContainer components = null;
+
+        /// <summary>
+        /// Clean up any resources being used.
+        /// </summary>
+        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing && (components != null))
+            {
+                components.Dispose();
+            }
+            base.Dispose(disposing);
+        }
+
+        #region Windows Form Designer generated code
+
+        /// <summary>
+        /// Required method for Designer support - do not modify
+        /// the contents of this method with the code editor.
+        /// </summary>
+        private void InitializeComponent()
+        {
+            this.button1 = new System.Windows.Forms.Button();
+            this.textBox1 = new System.Windows.Forms.TextBox();
+            this.SuspendLayout();
+            // 
+            // button1
+            // 
+            this.button1.Location = new System.Drawing.Point(57, 165);
+            this.button1.Name = "button1";
+            this.button1.Size = new System.Drawing.Size(75, 23);
+            this.button1.TabIndex = 0;
+            this.button1.Text = "button1";
+            this.button1.UseVisualStyleBackColor = true;
+            this.button1.Click += new System.EventHandler(this.button1_Click);
+            // 
+            // textBox1
+            // 
+            this.textBox1.Location = new System.Drawing.Point(57, 136);
+            this.textBox1.Name = "textBox1";
+            this.textBox1.Size = new System.Drawing.Size(217, 23);
+            this.textBox1.TabIndex = 1;
+            // 
+            // FormBad
+            // 
+            this.AutoScaleDimensions = new System.Drawing.SizeF(7F, 15F);
+            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
+            this.ClientSize = new System.Drawing.Size(800, 450);
+            this.Controls.Add(this.textBox1);
+            this.Controls.Add(this.button1);
+            this.Name = "FormBad";
+            this.Text = "FormBad";
+            this.ResumeLayout(false);
+            this.PerformLayout();
+
+        }
+
+        #endregion
+
+        private System.Windows.Forms.Button button1;
+        private System.Windows.Forms.TextBox textBox1;
+    }
+}
@@ -0,0 +1,31 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Data;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+
+namespace project
+{
+    public partial class FormBad : Form
+    {
+        public FormBad()
+        {
+            InitializeComponent();
+        }
+
+        //<Bad>
+        private void button1_Click(object sender, EventArgs e)
+        {
+            var thread2 = new System.Threading.Thread(WriteTextUnsafe);
+            thread2.Start();
+        }
+
+        private void WriteTextUnsafe() =>
+            textBox1.Text = "This text was set unsafely.";
+        //</Bad>
+    }
+}
@@ -0,0 +1,60 @@
+<root>
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+</root>
@@ -0,0 +1,73 @@
+
+namespace project
+{
+    partial class FormThread
+    {
+        /// <summary>
+        /// Required designer variable.
+        /// </summary>
+        private System.ComponentModel.IContainer components = null;
+
+        /// <summary>
+        /// Clean up any resources being used.
+        /// </summary>
+        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing && (components != null))
+            {
+                components.Dispose();
+            }
+            base.Dispose(disposing);
+        }
+
+        #region Windows Form Designer generated code
+
+        /// <summary>
+        /// Required method for Designer support - do not modify
+        /// the contents of this method with the code editor.
+        /// </summary>
+        private void InitializeComponent()
+        {
+            this.button1 = new System.Windows.Forms.Button();
+            this.textBox1 = new System.Windows.Forms.TextBox();
+            this.SuspendLayout();
+            // 
+            // button1
+            // 
+            this.button1.Location = new System.Drawing.Point(21, 84);
+            this.button1.Name = "button1";
+            this.button1.Size = new System.Drawing.Size(75, 23);
+            this.button1.TabIndex = 0;
+            this.button1.Text = "button1";
+            this.button1.UseVisualStyleBackColor = true;
+            this.button1.Click += new System.EventHandler(this.button1_Click);
+            // 
+            // textBox1
+            // 
+            this.textBox1.Location = new System.Drawing.Point(21, 55);
+            this.textBox1.Name = "textBox1";
+            this.textBox1.Size = new System.Drawing.Size(267, 23);
+            this.textBox1.TabIndex = 1;
+            this.textBox1.Enter += new System.EventHandler(this.textBox1_Enter);
+            // 
+            // FormThread
+            // 
+            this.AutoScaleDimensions = new System.Drawing.SizeF(7F, 15F);
+            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
+            this.ClientSize = new System.Drawing.Size(800, 450);
+            this.Controls.Add(this.textBox1);
+            this.Controls.Add(this.button1);
+            this.Name = "FormThread";
+            this.Text = "FormThread";
+            this.ResumeLayout(false);
+            this.PerformLayout();
+
+        }
+
+        #endregion
+
+        private System.Windows.Forms.Button button1;
+        private System.Windows.Forms.TextBox textBox1;
+    }
+}
@@ -0,0 +1,50 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Data;
+using System.Drawing;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+
+namespace project
+{
+    public partial class FormThread : Form
+    {
+        public FormThread()
+        {
+            InitializeComponent();
+        }
+
+        //<Good>
+        private void button1_Click(object sender, EventArgs e)
+        {
+            var threadParameters = new System.Threading.ThreadStart(delegate { WriteTextSafe("This text was set safely."); });
+            var thread2 = new System.Threading.Thread(threadParameters);
+            thread2.Start();
+        }
+
+        public void WriteTextSafe(string text)
+        {
+            if (textBox1.InvokeRequired)
+            {
+                // Call this same method but append THREAD2 to the text
+                Action safeWrite = delegate { WriteTextSafe($"{text} (THREAD2)"); };
+                textBox1.Invoke(safeWrite);
+            }
+            else
+                textBox1.Text = text;
+        }
+        //</Good>
+
+        private void textBox1_Enter(object sender, System.EventArgs e)
+        {
+            //if (!String.IsNullOrEmpty(textBox1.Text))
+            //{
+            //    textBox1.SelectionStart = 0;
+            //    textBox1.SelectionLength = textBox1.Text.Length;
+            //}
+        }
+    }
+}
@@ -0,0 +1,60 @@
+<root>
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+</root>
@@ -0,0 +1,23 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+
+namespace project
+{
+    static class Program
+    {
+        /// <summary>
+        ///  The main entry point for the application.
+        /// </summary>
+        [STAThread]
+        static void Main()
+        {
+            Application.SetHighDpiMode(HighDpiMode.SystemAware);
+            Application.EnableVisualStyles();
+            Application.SetCompatibleTextRenderingDefault(false);
+            Application.Run(new FormBackgroundWorker());
+        }
+    }
+}
@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>WinExe</OutputType>
+    <TargetFramework>net5.0-windows</TargetFramework>
+    <UseWindowsForms>true</UseWindowsForms>
+  </PropertyGroup>
+
+</Project>
@@ -0,0 +1,67 @@
+<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
+Partial Class FormBackgroundWorker
+    Inherits System.Windows.Forms.Form
+
+    'Form overrides dispose to clean up the component list.
+    <System.Diagnostics.DebuggerNonUserCode()> _
+    Protected Overrides Sub Dispose(ByVal disposing As Boolean)
+        Try
+            If disposing AndAlso components IsNot Nothing Then
+                components.Dispose()
+            End If
+        Finally
+            MyBase.Dispose(disposing)
+        End Try
+    End Sub
+
+    'Required by the Windows Form Designer
+    Private components As System.ComponentModel.IContainer
+
+    'NOTE: The following procedure is required by the Windows Form Designer
+    'It can be modified using the Windows Form Designer.  
+    'Do not modify it using the code editor.
+    <System.Diagnostics.DebuggerStepThrough()> _
+    Private Sub InitializeComponent()
+        Me.Button1 = New System.Windows.Forms.Button()
+        Me.TextBox1 = New System.Windows.Forms.TextBox()
+        Me.BackgroundWorker1 = New System.ComponentModel.BackgroundWorker()
+        Me.SuspendLayout()
+        '
+        'Button1
+        '
+        Me.Button1.Location = New System.Drawing.Point(28, 81)
+        Me.Button1.Name = "Button1"
+        Me.Button1.Size = New System.Drawing.Size(75, 23)
+        Me.Button1.TabIndex = 0
+        Me.Button1.Text = "Button1"
+        Me.Button1.UseVisualStyleBackColor = True
+        '
+        'TextBox1
+        '
+        Me.TextBox1.Location = New System.Drawing.Point(28, 52)
+        Me.TextBox1.Name = "TextBox1"
+        Me.TextBox1.Size = New System.Drawing.Size(312, 23)
+        Me.TextBox1.TabIndex = 1
+        '
+        'BackgroundWorker1
+        '
+        Me.BackgroundWorker1.WorkerReportsProgress = True
+        '
+        'FormBackgroundWorker
+        '
+        Me.AutoScaleDimensions = New System.Drawing.SizeF(7.0!, 15.0!)
+        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
+        Me.ClientSize = New System.Drawing.Size(800, 450)
+        Me.Controls.Add(Me.TextBox1)
+        Me.Controls.Add(Me.Button1)
+        Me.Name = "FormBackgroundWorker"
+        Me.Text = "FormBackgroundWorker"
+        Me.ResumeLayout(False)
+        Me.PerformLayout()
+
+    End Sub
+
+    Friend WithEvents Button1 As Windows.Forms.Button
+    Friend WithEvents TextBox1 As Windows.Forms.TextBox
+    Friend WithEvents BackgroundWorker1 As ComponentModel.BackgroundWorker
+End Class
@@ -0,0 +1,63 @@
+<root>
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <metadata name="BackgroundWorker1.TrayLocation" type="System.Drawing.Point, System.Drawing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a">
+    <value>17, 17</value>
+  </metadata>
+</root>
@@ -0,0 +1,31 @@
+Public Class FormBackgroundWorker
+    '<Background>
+    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
+
+        If (Not BackgroundWorker1.IsBusy) Then
+            BackgroundWorker1.RunWorkerAsync()
+        End If
+
+    End Sub
+
+    Private Sub BackgroundWorker1_DoWork(sender As Object, e As ComponentModel.DoWorkEventArgs) Handles BackgroundWorker1.DoWork
+
+        Dim counter = 0
+        Dim max = 10
+
+        While counter <= max
+
+            BackgroundWorker1.ReportProgress(0, counter.ToString())
+            System.Threading.Thread.Sleep(1000)
+
+            counter += 1
+
+        End While
+
+    End Sub
+
+    Private Sub BackgroundWorker1_ProgressChanged(sender As Object, e As ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
+        TextBox1.Text = e.UserState
+    End Sub
+    '</Background>
+End Class
@@ -0,0 +1,61 @@
+<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
+Partial Class FormBad
+    Inherits System.Windows.Forms.Form
+
+    'Form overrides dispose to clean up the component list.
+    <System.Diagnostics.DebuggerNonUserCode()> _
+    Protected Overrides Sub Dispose(ByVal disposing As Boolean)
+        Try
+            If disposing AndAlso components IsNot Nothing Then
+                components.Dispose()
+            End If
+        Finally
+            MyBase.Dispose(disposing)
+        End Try
+    End Sub
+
+    'Required by the Windows Form Designer
+    Private components As System.ComponentModel.IContainer
+
+    'NOTE: The following procedure is required by the Windows Form Designer
+    'It can be modified using the Windows Form Designer.  
+    'Do not modify it using the code editor.
+    <System.Diagnostics.DebuggerStepThrough()> _
+    Private Sub InitializeComponent()
+        Me.TextBox1 = New System.Windows.Forms.TextBox()
+        Me.Button1 = New System.Windows.Forms.Button()
+        Me.SuspendLayout()
+        '
+        'TextBox1
+        '
+        Me.TextBox1.Location = New System.Drawing.Point(25, 43)
+        Me.TextBox1.Name = "TextBox1"
+        Me.TextBox1.Size = New System.Drawing.Size(249, 23)
+        Me.TextBox1.TabIndex = 0
+        '
+        'Button1
+        '
+        Me.Button1.Location = New System.Drawing.Point(25, 72)
+        Me.Button1.Name = "Button1"
+        Me.Button1.Size = New System.Drawing.Size(75, 23)
+        Me.Button1.TabIndex = 1
+        Me.Button1.Text = "Button1"
+        Me.Button1.UseVisualStyleBackColor = True
+        '
+        'FormBad
+        '
+        Me.AutoScaleDimensions = New System.Drawing.SizeF(7.0!, 15.0!)
+        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
+        Me.ClientSize = New System.Drawing.Size(800, 450)
+        Me.Controls.Add(Me.Button1)
+        Me.Controls.Add(Me.TextBox1)
+        Me.Name = "FormBad"
+        Me.Text = "FormBad"
+        Me.ResumeLayout(False)
+        Me.PerformLayout()
+
+    End Sub
+
+    Friend WithEvents TextBox1 As Windows.Forms.TextBox
+    Friend WithEvents Button1 As Windows.Forms.Button
+End Class
@@ -0,0 +1,60 @@
+<root>
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+</root>
@@ -0,0 +1,12 @@
+Public Class FormBad
+    '<Bad>
+    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
+        Dim thread2 As New System.Threading.Thread(AddressOf WriteTextUnsafe)
+        thread2.Start()
+    End Sub
+
+    Private Sub WriteTextUnsafe()
+        TextBox1.Text = "This text was set unsafely."
+    End Sub
+    '</Bad>
+End Class
@@ -0,0 +1,61 @@
+<Global.Microsoft.VisualBasic.CompilerServices.DesignerGenerated()> _
+Partial Class FormThread
+    Inherits System.Windows.Forms.Form
+
+    'Form overrides dispose to clean up the component list.
+    <System.Diagnostics.DebuggerNonUserCode()> _
+    Protected Overrides Sub Dispose(ByVal disposing As Boolean)
+        Try
+            If disposing AndAlso components IsNot Nothing Then
+                components.Dispose()
+            End If
+        Finally
+            MyBase.Dispose(disposing)
+        End Try
+    End Sub
+
+    'Required by the Windows Form Designer
+    Private components As System.ComponentModel.IContainer
+
+    'NOTE: The following procedure is required by the Windows Form Designer
+    'It can be modified using the Windows Form Designer.  
+    'Do not modify it using the code editor.
+    <System.Diagnostics.DebuggerStepThrough()> _
+    Private Sub InitializeComponent()
+        Me.Button1 = New System.Windows.Forms.Button()
+        Me.TextBox1 = New System.Windows.Forms.TextBox()
+        Me.SuspendLayout()
+        '
+        'Button1
+        '
+        Me.Button1.Location = New System.Drawing.Point(27, 82)
+        Me.Button1.Name = "Button1"
+        Me.Button1.Size = New System.Drawing.Size(75, 23)
+        Me.Button1.TabIndex = 0
+        Me.Button1.Text = "Button1"
+        Me.Button1.UseVisualStyleBackColor = True
+        '
+        'TextBox1
+        '
+        Me.TextBox1.Location = New System.Drawing.Point(27, 53)
+        Me.TextBox1.Name = "TextBox1"
+        Me.TextBox1.Size = New System.Drawing.Size(235, 23)
+        Me.TextBox1.TabIndex = 1
+        '
+        'FormThread
+        '
+        Me.AutoScaleDimensions = New System.Drawing.SizeF(7.0!, 15.0!)
+        Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
+        Me.ClientSize = New System.Drawing.Size(800, 450)
+        Me.Controls.Add(Me.TextBox1)
+        Me.Controls.Add(Me.Button1)
+        Me.Name = "FormThread"
+        Me.Text = "FormThread"
+        Me.ResumeLayout(False)
+        Me.PerformLayout()
+
+    End Sub
+
+    Friend WithEvents Button1 As Windows.Forms.Button
+    Friend WithEvents TextBox1 As Windows.Forms.TextBox
+End Class
@@ -0,0 +1,60 @@
+<root>
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+</root>
@@ -0,0 +1,28 @@
+Public Class FormThread
+    '<Good>
+    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
+
+        Dim threadParameters As New System.Threading.ThreadStart(Sub()
+                                                                     WriteTextSafe("This text was set safely.")
+                                                                 End Sub)
+
+        Dim thread2 As New System.Threading.Thread(threadParameters)
+        thread2.Start()
+
+    End Sub
+
+    Private Sub WriteTextSafe(text As String)
+
+        If (TextBox1.InvokeRequired) Then
+
+            TextBox1.Invoke(Sub()
+                                WriteTextSafe($"{text} (THREAD2)")
+                            End Sub)
+
+        Else
+            TextBox1.Text = text
+        End If
+
+    End Sub
+    '</Good>
+End Class
@@ -0,0 +1,15 @@
+Imports System
+Imports System.Collections.Generic
+Imports System.Linq
+Imports System.Threading.Tasks
+Imports System.Windows.Forms
+
+Module Program
+    Sub Main(args As String())
+        Application.SetHighDpiMode(HighDpiMode.SystemAware)
+        Application.EnableVisualStyles()
+        Application.SetCompatibleTextRenderingDefault(False)
+        Application.Run(New FormBackgroundWorker())
+    End Sub
+
+End Module
@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>WinExe</OutputType>
+    <TargetFramework>net5.0-windows</TargetFramework>
+    <UseWindowsForms>true</UseWindowsForms>
+    <StartupObject>project.Program</StartupObject>
+  </PropertyGroup>
+
+</Project>
@@ -59,6 +59,8 @@ items:
      href: controls/how-to-add-a-picture-to-a-control.md
    - name: Add or remove event handlers
      href: controls/how-to-add-an-event-handler.md
+    - name: Make thread-safe calls to controls
+      href: controls/how-to-make-thread-safe-calls.md
 - name: User input - keyboard
  items:
  - name: Overview