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Control.ProcessMnemonic(Char) Method

  • Reference

Definition

Namespace:
System.Windows.Forms
Assembly:
System.Windows.Forms.dll
Source:
Control.cs
Source:
Control.cs
Source:
Control.cs

Processes a mnemonic character.

protected:
 virtual bool ProcessMnemonic(char charCode);
protected public:
 virtual bool ProcessMnemonic(char charCode);
protected virtual bool ProcessMnemonic (char charCode);
protected internal virtual bool ProcessMnemonic (char charCode);
abstract member ProcessMnemonic : char -> bool
override this.ProcessMnemonic : char -> bool
Protected Overridable Function ProcessMnemonic (charCode As Char) As Boolean
Protected Friend Overridable Function ProcessMnemonic (charCode As Char) As Boolean

Parameters

charCode
Char

The character to process.

Returns

Boolean

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

Examples

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.  
// This method makes sure the control is selectable and the 
// mnemonic is correct before displaying the message box
// and triggering the click event.
public ref class MyMnemonicButton: public Button
{
protected:
   bool ProcessMnemonic( char inputChar )
   {
      if ( CanSelect && IsMnemonic( inputChar, this->Text ) )
      {
         MessageBox::Show( "You've raised the click event "
         "using the mnemonic." );
         this->PerformClick();
         return true;
      }

      return false;
   }

};

// 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 : Button
{
    // This method makes sure the control is selectable and the 
    // mneumonic is correct before displaying the message box
    // and triggering the click event.
    protected override bool ProcessMnemonic(char inputChar)
    {
        if (CanSelect && IsMnemonic(inputChar, this.Text))
        {
            MessageBox.Show("You've raised the click event " +
                "using the mnemonic.");
            this.PerformClick();
            return true;
        }
        return false;
    }
}

' 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

Remarks

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.

Applies to

See also