docs-desktop/dotnet-desktop-guide/framework/winforms/controls/walkthrough-working-with-the-maskedtextbox-control.md

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title	ms.date	dev_langs	helpviewer_keywords	ms.assetid
Walkthrough: Working with the MaskedTextBox Control	03/30/2017	csharp vb	input [Windows Forms], controlling to ensure validity MaskedTextBox control [Windows Forms], walkthroughs MaskedTextBox control [Windows Forms], validation user input [Windows Forms], controlling text [Windows Forms], controls for input	df60565e-5447-4110-92a6-be1f6ff5faa3

Walkthrough: Working with the MaskedTextBox Control

Tasks illustrated in this walkthrough include:

• Initializing the xref:System.Windows.Forms.MaskedTextBox control

• Using the xref:System.Windows.Forms.MaskedTextBox.MaskInputRejected event handler to alert the user when a character does not conform to the mask

• Assigning a type to the xref:System.Windows.Forms.MaskedTextBox.ValidatingType%2A property and using the xref:System.Windows.Forms.MaskedTextBox.TypeValidationCompleted event handler to alert the user when the value they're attempting to commit is not valid for the type

Creating the Project and Adding a Control

To add a MaskedTextBox control to your form

1. Open the form on which you want to place the xref:System.Windows.Forms.MaskedTextBox control.

2. Drag a xref:System.Windows.Forms.MaskedTextBox control from the Toolbox to your form.

3. Right-click the control and choose Properties. In the Properties window, select the Mask property and click the ... (ellipsis) button next to the property name.

4. In the Input Mask dialog box, select the Short Date mask and click OK.

5. In the Properties window set the xref:System.Windows.Forms.MaskedTextBox.BeepOnError%2A property to true. This property causes a short beep to sound every time the user attempts to input a character that violates the mask definition.

For a summary of the characters that the Mask property supports, see the Remarks section of the xref:System.Windows.Forms.MaskedTextBox.Mask%2A property.

Alert the User to Input Errors

Add a balloon tip for rejected mask input

1. Return to the Toolbox and add a xref:System.Windows.Forms.ToolTip to your form.

2. Create an event handler for the xref:System.Windows.Forms.MaskedTextBox.MaskInputRejected event that raises the xref:System.Windows.Forms.ToolTip when an input error occurs. The balloon tip remains visible for five seconds, or until the user clicks it.

   public void Form1_Load(Object sender, EventArgs e)
   {  
       ... // Other initialization code  
       maskedTextBox1.Mask = "00/00/0000";  
       maskedTextBox1.MaskInputRejected += new MaskInputRejectedEventHandler(maskedTextBox1_MaskInputRejected)  
   }  
   
   void maskedTextBox1_MaskInputRejected(object sender, MaskInputRejectedEventArgs e)  
   {  
       toolTip1.ToolTipTitle = "Invalid Input";  
       toolTip1.Show("We're sorry, but only digits (0-9) are allowed in dates.", maskedTextBox1, maskedTextBox1.Location, 5000);  
   }  
   

   Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load  
       Me.ToolTip1.IsBalloon = True  
       Me.MaskedTextBox1.Mask = "00/00/0000"  
   End Sub  
   
   Private Sub MaskedTextBox1_MaskInputRejected(sender as Object, e as MaskInputRejectedEventArgs) Handles MaskedTextBox1.MaskInputRejected  
       ToolTip1.ToolTipTitle = "Invalid Input"  
       ToolTip1.Show("We're sorry, but only digits (0-9) are allowed in dates.", MaskedTextBox1, 5000)  
   End Sub  
   

Alert the User to a Type that Is Not Valid

Add a balloon tip for invalid data types

1. In your form's xref:System.Windows.Forms.Form.Load event handler, assign a xref:System.Type object representing the xref:System.DateTime type to the xref:System.Windows.Forms.MaskedTextBox control's xref:System.Windows.Forms.MaskedTextBox.ValidatingType%2A property:

   private void Form1_Load(Object sender, EventArgs e)  
   {  
       // Other code  
       maskedTextBox1.ValidatingType = typeof(System.DateTime);  
       maskedTextBox1.TypeValidationCompleted += new TypeValidationEventHandler(maskedTextBox1_TypeValidationCompleted);  
   }  
   

   Private Sub Form1_Load(sender as Object, e as EventArgs)  
       // Other code  
       MaskedTextBox1.ValidatingType = GetType(System.DateTime)  
   End Sub  
   

2. Add an event handler for the xref:System.Windows.Forms.MaskedTextBox.TypeValidationCompleted event:

   public void maskedTextBox1_TypeValidationCompleted(object sender, TypeValidationEventArgs e)  
   {  
       if (!e.IsValidInput)  
       {  
          toolTip1.ToolTipTitle = "Invalid Date Value";  
          toolTip1.Show("We're sorry, but the value you entered is not a valid date. Please change the value.", maskedTextBox1, 5000);  
          e.Cancel = true;  
       }  
   }  
   

   Public Sub MaskedTextBox1_TypeValidationCompleted(sender as Object, e as TypeValidationEventArgs)  
       If Not e.IsValidInput Then  
          ToolTip1.ToolTipTitle = "Invalid Date Value"  
          ToolTip1.Show("We're sorry, but the value you entered is not a valid date. Please change the value.", maskedTextBox1, 5000)  
          e.Cancel = True  
       End If  
   End Sub  
   

See also

• xref:System.Windows.Forms.MaskedTextBox
• MaskedTextBox Control