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Control.ProcessMnemonic Method

Processes a mnemonic character.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

'Declaration
<UIPermissionAttribute(SecurityAction.InheritanceDemand, Window := UIPermissionWindow.AllWindows)> _
<UIPermissionAttribute(SecurityAction.LinkDemand, Window := UIPermissionWindow.AllWindows)> _
Protected Friend Overridable Function ProcessMnemonic ( _
	charCode As Char _
) As Boolean

Parameters

charCode
Type: System.Char

The character to process.

Return Value

Type: System.Boolean
true if the character was processed as a mnemonic by the control; otherwise, false.

This method is called to give a control the opportunity to process a mnemonic character. The method should determine whether the control is in a state to process mnemonics and if whether the given character represents a mnemonic. If so, the method should perform the action associated with the mnemonic and return true. If not, the method should return false. Implementations of this method often use the IsMnemonic method to determine whether the given character matches a mnemonic in the control's text.

For example:

if (CanSelect && IsMnemonic(charCode, MyControl.Text) {
      // Perform action associated with mnemonic.
       }

This default implementation of the ProcessMnemonic method simply returns false to indicate that the control has no mnemonic.

The following code example demonstrates an extension of the button class that overrides the ProcessMnemonic method to exhibit custom behavior. The example also demonstrates the use of the CanSelect and IsMnemonic properties. To run this example paste the following code after a form class, in the same file. Add a button of type MnemonicButton to the form.

' This button is a simple extension of the button class that overrides 
' the ProcessMnemonic method.  If the mnemonic is correctly entered,   
' the message box will appear and the click event will be raised.   
Public Class MyMnemonicButton
    Inherits Button

    ' This method makes sure the control is selectable and the  
    ' mneumonic is correct before displaying the message box 
    ' and triggering the click event.
    <System.Security.Permissions.UIPermission( _
    System.Security.Permissions.SecurityAction.Demand, Window:=UIPermissionWindow.AllWindows)> _
    Protected Overrides Function ProcessMnemonic( _
        ByVal inputChar As Char) As Boolean 

        If (CanSelect And IsMnemonic(inputChar, Me.Text)) Then
            MessageBox.Show("You've raised the click event " _
                & "using the mnemonic.")
            Me.PerformClick()
            Return True 
        End If 
        Return False 
    End Function 

End Class
To run this example paste the following code after a form class, in the same file.  Add a button of type MnemonicButton to the form.

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0, 1.1

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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