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IVideoWindow::put_MessageDrain method (control.h)

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[The feature associated with this page, DirectShow, is a legacy feature. It has been superseded by MediaPlayer, IMFMediaEngine, and Audio/Video Capture in Media Foundation. Those features have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer, IMFMediaEngine and Audio/Video Capture in Media Foundation instead of DirectShow, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The put_MessageDrain method specifies a window to receive mouse and keyboard messages from the video window.

Syntax

HRESULT put_MessageDrain(
  [in] OAHWND Drain
);

Parameters

[in] Drain

A handle to the window, as an OAHWND value.

Return value

Possible return values include the following:

Return code Description
S_OK
 Success.
VFW_E_NOT_CONNECTED
 The video renderer filter is not connected.

Remarks

This method enables an application to respond to mouse and keyboard events generated within the video window.

If Drain is non-NULL, the video renderer forwards certain messages to the specified window, using the PostMessage function. Which messages are forwarded might depend on the video renderer in use. The Video Renderer and Video Mixing Renderer (VMR) filters forward the following messages:

  • WM_CHAR
  • WM_DEADCHAR
  • WM_KEYDOWN
  • WM_KEYUP
  • WM_LBUTTONDBLCLK
  • WM_LBUTTONDOWN
  • WM_LBUTTONUP
  • WM_MBUTTONDBLCLK
  • WM_MBUTTONDOWN
  • WM_MBUTTONUP
  • WM_MOUSEACTIVATE
  • WM_MOUSEMOVE
  • WM_NCLBUTTONDBLCLK
  • WM_NCLBUTTONDOWN
  • WM_NCLBUTTONUP
  • WM_NCMBUTTONDBLCLK
  • WM_NCMBUTTONDOWN
  • WM_NCMBUTTONUP
  • WM_NCMOUSEMOVE
  • WM_NCRBUTTONDBLCLK
  • WM_NCRBUTTONDOWN
  • WM_NCRBUTTONUP
  • WM_RBUTTONDBLCLK
  • WM_RBUTTONDOWN
  • WM_RBUTTONUP
  • WM_SYSCHAR
  • WM_SYSDEADCHAR
  • WM_SYSKEYDOWN
  • WM_SYSKEYUP
The message drain window does not need to be a parent of the video window, so full-screen applications can use this method.

Requirements

Requirement Value
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Target Platform Windows
Header control.h (include Dshow.h)
Library Strmiids.lib

See also

Error and Success Codes

IVideoWindow Interface

IVideoWindow::get_MessageDrain