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how-to-handle-keyboard-input-at-the-form-level.md

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title description ms.date dev_langs helpviewer_keywords ms.assetid
How to: Handle Keyboard Input at the Form Level
Learn how to handle keyboard input for your Windows Forms at the form level, before messages reach a control.
03/30/2017
csharp
vb
cpp
keyboard input [Windows Forms], at form level
Windows Forms, handling keyboard input
keyboards [Windows Forms], form-level input
d7f8b390-dc91-42d2-ae0f-2ffa388127ad

How to: Handle Keyboard Input at the Form Level

Windows Forms provides the ability to handle keyboard messages at the form level, before the messages reach a control. This topic shows how to accomplish this task.

To handle a keyboard message at the form level

  • Handle the xref:System.Windows.Forms.Control.KeyPress or xref:System.Windows.Forms.Control.KeyDown event of the startup form, and set the xref:System.Windows.Forms.Form.KeyPreview%2A property of the form to true so that keyboard messages are received by the form before they reach any controls on the form. The following code example handles the xref:System.Windows.Forms.Control.KeyPress event by detecting all of the number keys and consuming '1', '4', and '7'.

    [!code-cppSystem.Windows.Forms.KeyboardInputForm#10] [!code-csharpSystem.Windows.Forms.KeyboardInputForm#10] [!code-vbSystem.Windows.Forms.KeyboardInputForm#10]

Example

The following code example is the entire application for the above example. The application includes a xref:System.Windows.Forms.TextBox along with several other controls that allow you to move focus from the xref:System.Windows.Forms.TextBox. The xref:System.Windows.Forms.Control.KeyPress event of the main xref:System.Windows.Forms.Form consumes '1', '4', and '7', and the xref:System.Windows.Forms.Control.KeyPress event of the xref:System.Windows.Forms.TextBox consumes '2', '5', and '8' while displaying the remaining keys. Compare the xref:System.Windows.Forms.MessageBox output when you press a number key while the xref:System.Windows.Forms.TextBox has focus with the xref:System.Windows.Forms.MessageBox output when you press a number key while focus is on one of the other controls.

[!code-cppSystem.Windows.Forms.KeyBoardInputForm#0] [!code-csharpSystem.Windows.Forms.KeyBoardInputForm#0] [!code-vbSystem.Windows.Forms.KeyBoardInputForm#0]

Compiling the Code

This example requires:

  • References to the System, System.Drawing and System.Windows.Forms assemblies.

See also