How to process Windows messages using controls without window handles in Delphi

The timage control does not have a window function, so it cannot process messages. When a message is processed by its parent in winproc of its parent, getcontrolsatpos is used to obtain the control at the current mouse cursor. If the control is obtained, the perform function is used to send the modified message to this control (that is, to call the winproc function of the control). The winproc function of the control processes the message. Here, the dispatchmessage function is used to process the message, dispatchmessageCodeThe principle is to find the mark in the virtual method table.
Message wm_lbuttondown method and execute it.