Control.ProcessKeyPreview(Message) Method

Reference

Definition

Namespace:: System.Windows.Forms

Assembly:: System.Windows.Forms.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Previews a keyboard message.

protected:
 virtual bool ProcessKeyPreview(System::Windows::Forms::Message % m);

protected virtual bool ProcessKeyPreview (ref System.Windows.Forms.Message m);

abstract member ProcessKeyPreview : Message -> bool
override this.ProcessKeyPreview : Message -> bool

Protected Overridable Function ProcessKeyPreview (ByRef m As Message) As Boolean

Parameters

m: Message

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

Returns

Boolean

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

Remarks

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(Message) 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 ProcessKeyPreview(Message) method should be returned.

Applies to

Jaa