Andy (Steve) De George
d30fae457c
* Update with margin/padding * add how-to-make-thread-safe-calls * reverse property mentions
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title, description, ms.date, ms.topic, helpviewer_keywords
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| Control layout options | 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. | 07/19/2021 | overview |
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Position and layout of controls (Windows Forms .NET)
Control placement in Windows Forms is determined not only by the control, but also by the parent of the control. This article describes the different settings provided by controls and the different types of parent containers that affect layout.
[!INCLUDE desktop guide under construction]
Fixed position and size
The position a control appears on a parent is determined by the value of the xref:System.Windows.Forms.Control.Location property relative to the top-left of the parent surface. The top-left position coordinate in the parent is (x0,y0). The size of the control is determined by the xref:System.Windows.Forms.Control.Size property and represents the width and height of the control.
:::image type="content" source="media/layout/location+container.png" alt-text="Location of the control relative to the container":::
When a control is added to a parent that enforces automatic placement, the position and size of the control is changed. In this case, the position and size of the control may not be manually adjusted, depending on the type of parent.
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.
Drawing order can affect automatic placement. The order in which a control is drawn determined by the control's index in the parent's xref:System.Windows.Forms.Control.Controls collection. This index is known as the :::no-loc text="Z-order":::. Each control is drawn in the reverse order they appear in the collection. Meaning, the collection is a first-in-last-drawn and last-in-first-drawn collection.
The xref:System.Windows.Forms.Control.MinimumSize%2A and xref:System.Windows.Forms.Control.MaximumSize%2A properties help set the minimum and maximum space a control can use.
Dock
The Dock property sets which border of the control is aligned to the corresponding side of the parent, and how the control is resized within the parent.
:::image type="content" source="media/layout/dock-modes.png" alt-text="Windows form with buttons with dock settings.":::
When a control is docked, the container determines the space it should occupy and resizes and places the control. The width and height of the control are still respected based on the docking style. For example, if the control is docked to the top, the xref:System.Windows.Forms.Control.Height of the control is respected but the xref:System.Windows.Forms.Control.Width is automatically adjusted. If a control is docked to the left, the xref:System.Windows.Forms.Control.Width of the control is respected but the xref:System.Windows.Forms.Control.Height is automatically adjusted.
The xref:System.Windows.Forms.Control.Location of the control can't be manually set as docking a control automatically controls its position.
The :::no-loc text="Z-order"::: of the control does affect docking. As docked controls are laid out, they use what space is available to them. For example, if a control is drawn first and docked to the top, it will take up the entire width of the container. If a next control is docked to the left, it has less vertical space available to it.
:::image type="content" source="media/layout/dock-top-then-left.png" alt-text="Windows form with buttons docked to the left and top with top being bigger.":::
If the control's :::no-loc text="Z-order"::: is reversed, the control that is docked to the left now has more initial space available. The control uses the entire height of the container. The control that is docked to the top has less horizontal space available to it.
:::image type="content" source="media/layout/dock-left-then-top.png" alt-text="Windows form with buttons docked to the left and top with left being bigger.":::
As the container grows and shrinks, the controls docked to the container are repositioned and resized to maintain their applicable positions and sizes.
:::image type="content" source="media/layout/dock-resize.gif" alt-text="Animation showing how A Windows Form with buttons docked in all positions is resized.":::
If multiple controls are docked to the same side of the container, they're stacked according to their :::no-loc text="Z-order":::.
:::image type="content" source="media/layout/dock-left-left.png" alt-text="Windows form with two buttons docked to the left.":::
Anchor
Anchoring a control allows you to tie the control to one or more sides of the parent container. As the container changes in size, any child control will maintain its distance to the anchored side.
A control can be anchored to one or more sides, without restriction. The anchor is set with the xref:System.Windows.Forms.Control.Anchor property.
:::image type="content" source="media/layout/anchor-resize.gif" alt-text="Animation showing how A Windows Form with buttons anchored in all positions is resized.":::
Automatic sizing
The xref:System.Windows.Forms.Control.AutoSize property enables a control to change its size, if necessary, to fit the size specified by the xref:System.Windows.Forms.Control.PreferredSize property. You adjust the sizing behavior for specific controls by setting the AutoSizeMode property.
Only some controls support the xref:System.Windows.Forms.Control.AutoSize%2A property. In addition, some controls that support the xref:System.Windows.Forms.Control.AutoSize%2A property also supports the AutoSizeMode property.
| Always true behavior | Description |
|---|---|
| Automatic sizing is a run-time feature. | This means it never grows or shrinks a control and then has no further effect. |
| If a control changes size, the value of its xref:System.Windows.Forms.Control.Location%2A property always remains constant. | When a control's contents cause it to grow, the control grows toward the right and downward. Controls do not grow to the left. |
The xref:System.Windows.Forms.Control.Dock%2A and xref:System.Windows.Forms.Control.Anchor%2A properties are honored when xref:System.Windows.Forms.Control.AutoSize%2A is true. |
The value of the control's xref:System.Windows.Forms.Control.Location%2A property is adjusted to the correct value. The xref:System.Windows.Forms.Label control is the exception to this rule. When you set the value of a docked xref:System.Windows.Forms.Label control's xref:System.Windows.Forms.Control.AutoSize%2A property to true, the xref:System.Windows.Forms.Label control will not stretch. |
| A control's xref:System.Windows.Forms.Control.MaximumSize%2A and xref:System.Windows.Forms.Control.MinimumSize%2A properties are always honored, regardless of the value of its xref:System.Windows.Forms.Control.AutoSize%2A property. | The xref:System.Windows.Forms.Control.MaximumSize%2A and xref:System.Windows.Forms.Control.MinimumSize%2A properties are not affected by the xref:System.Windows.Forms.Control.AutoSize%2A property. |
| There is no minimum size set by default. | This means that if a control is set to shrink under xref:System.Windows.Forms.Control.AutoSize%2A and it has no contents, the value of its xref:System.Windows.Forms.Control.Size%2A property is (0x,0y). In this case, your control will shrink to a point, and it will not be readily visible. |
| If a control does not implement the xref:System.Windows.Forms.Control.GetPreferredSize%2A method, the xref:System.Windows.Forms.Control.GetPreferredSize%2A method returns last value assigned to the xref:System.Windows.Forms.Control.Size%2A property. | This means that setting xref:System.Windows.Forms.Control.AutoSize%2A to true will have no effect. |
| A control in a xref:System.Windows.Forms.TableLayoutPanel cell always shrinks to fit in the cell until its xref:System.Windows.Forms.Control.MinimumSize%2A is reached. | This size is enforced as a maximum size. This is not the case when the cell is part of an xref:System.Windows.Forms.SizeType.AutoSize row or column. |
AutoSizeMode property
The xref:System.Windows.Forms.AutoSizeMode property provides more fine-grained control over the default xref:System.Windows.Forms.Control.AutoSize%2A behavior. The AutoSizeMode property specifies how a control sizes itself to its content. The content, for example, could be the text for a xref:System.Windows.Forms.Button control or the child controls for a container.
The following list shows the AutoSizeMode values and its behavior.
-
xref:System.Windows.Forms.AutoSizeMode.GrowAndShrink?displayProperty=nameWithType
The control grows or shrinks to encompass its contents.
The xref:System.Windows.Forms.Control.MinimumSize%2A and xref:System.Windows.Forms.Control.MaximumSize%2A values are honored, but the current value of the xref:System.Windows.Forms.Control.Size%2A property is ignored.
This is the same behavior as controls with the xref:System.Windows.Forms.Control.AutoSize%2A property and no
AutoSizeModeproperty. -
xref:System.Windows.Forms.AutoSizeMode.GrowOnly?displayProperty=nameWithType
The control grows as much as necessary to encompass its contents, but it will not shrink smaller than the value specified by its xref:System.Windows.Forms.Control.Size%2A property.
This is the default value for
AutoSizeMode.
Controls that support the AutoSize property
The following table describes the level of auto sizing support by control:
AutoSize in the design environment
The following table describes the sizing behavior of a control at design time, based on the value of its xref:System.Windows.Forms.Control.AutoSize%2A and AutoSizeMode properties.
Override the xref:System.Windows.Forms.Design.ControlDesigner.SelectionRules%2A property to determine whether a given control is in a user-resizable state. In the following table, "can't resize" means xref:System.Windows.Forms.Design.SelectionRules.Moveable only, "can resize" means xref:System.Windows.Forms.Design.SelectionRules.AllSizeable and xref:System.Windows.Forms.Design.SelectionRules.Moveable.
AutoSize setting |
AutoSizeMode setting |
Behavior |
|---|---|---|
true |
Property not available. | The user can't resize the control at design time, except for the following controls: - xref:System.Windows.Forms.TextBox - xref:System.Windows.Forms.MaskedTextBox - xref:System.Windows.Forms.RichTextBox - xref:System.Windows.Forms.TrackBar |
true |
xref:System.Windows.Forms.AutoSizeMode.GrowAndShrink | The user can't resize the control at design time. |
true |
xref:System.Windows.Forms.AutoSizeMode.GrowOnly | The user can resize the control at design time. When the xref:System.Windows.Forms.Control.Size%2A property is set, the user can only increase the size of the control. |
false or AutoSize is hidden |
Not applicable. | User can resize the control at design time. |
Note
To maximize productivity, the Windows Forms Designer in Visual Studio shadows the xref:System.Windows.Forms.Control.AutoSize%2A property for the xref:System.Windows.Forms.Form class. At design time, the form behaves as though the xref:System.Windows.Forms.Control.AutoSize%2A property is set to
false, regardless of its actual setting. At runtime, no special accommodation is made, and the xref:System.Windows.Forms.Control.AutoSize%2A property is applied as specified by the property setting.
Container: Form
The xref:System.Windows.Forms.Form is the main object of Windows Forms. A Windows Forms application will usually have a form displayed at all times. Forms contain controls and respect the xref:System.Windows.Forms.Control.Location and xref:System.Windows.Forms.Control.Size properties of the control for manual placement. Forms also respond to the Dock property for automatic placement.
Most of the time a form will have grips on the edges that allow the user to resize the form. The xref:System.Windows.Forms.Control.Anchor property of a control will let the control grow and shrink as the form is resized.
Container: Panel
The xref:System.Windows.Forms.Panel control is similar to a form in that it simply groups controls together. It supports the same manual and automatic placement styles that a form does. For more information, see the Container: Form section.
A panel blends in seamlessly with the parent, and it does cut off any area of a control that falls out of bounds of the panel. If a control falls outside the bounds of the panel and xref:System.Windows.Forms.Form.AutoScroll is set to true, scroll bars appear and the user can scroll the panel.
Unlike the group box control, a panel doesn't have a caption and border.
:::image type="content" source="media/layout/panel-groupbox.png" alt-text="A Windows Form with a panel and group box.":::
The image above has a panel with the xref:System.Windows.Forms.Panel.BorderStyle%2A property set to demonstrate the bounds of the panel.
Container: Group box
The xref:System.Windows.Forms.GroupBox control provides an identifiable grouping for other controls. Typically, you use a group box to subdivide a form by function. For example, you may have a form representing personal information and the fields related to an address would be grouped together. At design time, it's easy to move the group box around along with its contained controls.
The group box supports the same manual and automatic placement styles that a form does. For more information, see the Container: Form section. A group box also cuts off any portion of a control that falls out of bounds of the panel.
Unlike the panel control, a group box doesn't have the capability to scroll content and display scroll bars.
:::image type="content" source="media/layout/panel-groupbox.png" alt-text="A Windows Form with a panel and group box.":::
Container: Flow Layout
The xref:System.Windows.Forms.FlowLayoutPanel control arranges its contents in a horizontal or vertical flow direction. You can wrap the control's contents from one row to the next, or from one column to the next. Alternately, you can clip instead of wrap its contents.
You can specify the flow direction by setting the value of the xref:System.Windows.Forms.FlowLayoutPanel.FlowDirection%2A property. The xref:System.Windows.Forms.FlowLayoutPanel control correctly reverses its flow direction in Right-to-Left (RTL) layouts. You can also specify whether the xref:System.Windows.Forms.FlowLayoutPanel control's contents are wrapped or clipped by setting the value of the xref:System.Windows.Forms.FlowLayoutPanel.WrapContents%2A property.
The xref:System.Windows.Forms.FlowLayoutPanel control automatically sizes to its contents when you set the xref:System.Windows.Forms.Control.AutoSize%2A property to true. It also provides a FlowBreak property to its child controls. Setting the value of the FlowBreak property to true causes the xref:System.Windows.Forms.FlowLayoutPanel control to stop laying out controls in the current flow direction and wrap to the next row or column.
:::image type="content" source="media/layout/flow.png" alt-text="A Windows Form with two flow panel controls.":::
The image above has two FlowLayoutPanel controls with the xref:System.Windows.Forms.Panel.BorderStyle property set to demonstrate the bounds of the control.
Container: Table layout
The xref:System.Windows.Forms.TableLayoutPanel control arranges its contents in a grid. Because the layout is done both at design time and run time, it can change dynamically as the application environment changes. This gives the controls in the panel the ability to resize proportionally, so they can respond to changes such as the parent control resizing or text length changing because of localization.
Any Windows Forms control can be a child of the xref:System.Windows.Forms.TableLayoutPanel control, including other instances of xref:System.Windows.Forms.TableLayoutPanel. This allows you to construct sophisticated layouts that adapt to changes at run time.
You can also control the direction of expansion (horizontal or vertical) after the xref:System.Windows.Forms.TableLayoutPanel control is full of child controls. By default, the xref:System.Windows.Forms.TableLayoutPanel control expands downward by adding rows.
You can control the size and style of the rows and columns by using the xref:System.Windows.Forms.TableLayoutPanel.RowStyles%2A and xref:System.Windows.Forms.TableLayoutPanel.ColumnStyles%2A properties. You can set the properties of rows or columns individually.
The xref:System.Windows.Forms.TableLayoutPanel control adds the following properties to its child controls: Cell, Column, Row, ColumnSpan, and RowSpan.
:::image type="content" source="media/layout/table.png" alt-text="A Windows Form with table layout control.":::
The image above has a table with the xref:System.Windows.Forms.TableLayoutPanel.CellBorderStyle property set to demonstrate the bounds of each cell.
Container: Split container
The Windows Forms xref:System.Windows.Forms.SplitContainer control can be thought of as a composite control; it's two panels separated by a movable bar. When the mouse pointer is over the bar, the pointer changes shape to show that the bar is movable.
With the xref:System.Windows.Forms.SplitContainer control, you can create complex user interfaces; often, a selection in one panel determines what objects are shown in the other panel. This arrangement is effective for displaying and browsing information. Having two panels lets you aggregate information in areas, and the bar, or "splitter," makes it easy for users to resize the panels.
:::image type="content" source="media/layout/splitcontainer.png" alt-text="A Windows Form with a nested split container.":::
The image above has a split container to create a left and right pane. The right pane contains a second split container with the xref:System.Windows.Forms.SplitContainer.Orientation set to xref:System.Windows.Forms.Orientation.Vertical. The xref:System.Windows.Forms.SplitContainer.BorderStyle property is set to demonstrate the bounds of each panel.
Container: Tab control
The xref:System.Windows.Forms.TabControl displays multiple tabs, like dividers in a notebook or labels in a set of folders in a filing cabinet. The tabs can contain pictures and other controls. Use the tab control to produce the kind of multiple-page dialog box that appears many places in the Windows operating system, such as the Control Panel and Display Properties. Additionally, the xref:System.Windows.Forms.TabControl can be used to create property pages, which are used to set a group of related properties.
The most important property of the xref:System.Windows.Forms.TabControl is xref:System.Windows.Forms.TabControl.TabPages%2A, which contains the individual tabs. Each individual tab is a xref:System.Windows.Forms.TabPage object.
:::image type="content" source="media/layout/tabcontrol.png" alt-text="A Windows Form with a tab control with two tab pages.":::