The Message Map

[The feature associated with this page, Windows Media Player SDK, is a legacy feature. It has been superseded by MediaPlayer. MediaPlayer has been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use MediaPlayer instead of Windows Media Player SDK, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]

The plug-in window responds to various events by calling methods that are mapped to corresponding event messages. The wizard provides a mapping so that OnPaint and OnEraseBackground will be called at the appropriate times. To create the Search button and to respond to clicks from it, the message map section is modified as follows:

BEGIN_MSG_MAP(CPluginWindow)
    MESSAGE_HANDLER(WM_PAINT, OnPaint)
    MESSAGE_HANDLER(WM_ERASEBKGND, OnEraseBackground)
    MESSAGE_HANDLER(WM_CREATE, OnCreate)
    COMMAND_ID_HANDLER(IDC_SEARCH, OnSearch)
END_MSG_MAP()

Implementing CPluginWindow