The WM_DRAWCLIPBOARD message is sent to the first window in the clipboard viewer chain when the content of the clipboard changes. This enables a clipboard viewer window to display the new content of the clipboard.
WM_DRAWCLIPBOARD
This message has no parameters.
Only clipboard viewer windows receive this message. These are windows that have been added to the clipboard viewer chain by using the SetClipboardViewer function.
Each window that receives the WM_DRAWCLIPBOARD message must call the SendMessage function to pass the message on to the next window in the clipboard viewer chain. The handle of the next window in the chain is returned by SetClipboardViewer, and may change in response to a WM_CHANGECBCHAIN message.