ProcessKeyPreview Method
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Control.ProcessKeyPreview Method

Previews a keyboard message.

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

virtual bool ProcessKeyPreview (
	Message% m
protected boolean ProcessKeyPreview (
	/** @ref */ Message m
JScript does not support passing value-type arguments by reference.



A Message, passed by reference, that represents the window message to process.

Return Value

true if the message was processed by the control; otherwise, false.

This method is called by a child control when the child control receives a keyboard message. The child control calls this method before generating any keyboard events for the message. If this method returns true, the child control considers the message processed and does not generate any keyboard events. The m parameter contains the window message to preview. Possible values for the Message.Msg property are WM_CHAR, WM_KEYDOWN, WM_SYSKEYDOWN, WM_KEYUP, and WM_SYSKEYUP. The ProcessKeyPreview method simply sends the character to the parent's ProcessKeyPreview method, or returns false if the control has no parent. The Form class overrides this method to perform actual processing of dialog keys.

Notes to Inheritors When overriding the ProcessKeyPreview method in a derived class, a control should return true to indicate that it has processed the key. For keys that are not processed by the control, the result of calling the base class's ProcessKeyEventArgs method should be returned.

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.

.NET Framework

Supported in: 2.0, 1.1, 1.0

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