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PreProcessMessage Method
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Control.PreProcessMessage Method

Preprocesses keyboard or input messages within the message loop before they are dispatched.

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

'Declaration
<SecurityPermissionAttribute(SecurityAction.InheritanceDemand, Flags := SecurityPermissionFlag.UnmanagedCode)> _
<SecurityPermissionAttribute(SecurityAction.LinkDemand, Flags := SecurityPermissionFlag.UnmanagedCode)> _
Public Overridable Function PreProcessMessage ( _
	ByRef msg As Message _
) As Boolean

Parameters

msg
Type: System.Windows.Forms.Message

A Message, passed by reference, that represents the message to process. The possible values are WM_KEYDOWN, WM_SYSKEYDOWN, WM_CHAR, and WM_SYSCHAR.

Return Value

Type: System.Boolean
true if the message was processed by the control; otherwise, false.

PreProcessMessage is called by the application's message loop to preprocess input messages before they are dispatched. Possible values for the msg parameter are WM_KEYDOWN, WM_SYSKEYDOWN, WM_CHAR, and WM_SYSCHAR.

When overriding PreProcessMessage, a control should return true to indicate that it has processed the message. For messages that are not processed by the control, the result of base.PreProcessMessage should be returned. Controls will typically override one of the more specialized methods such as IsInputChar, IsInputKey, ProcessCmdKey, ProcessDialogChar, or ProcessDialogKey instead of overriding PreProcessMessage.

.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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