As we know, MFC, WPF, or any mature application development framework, they provide XX_click, XX_doubleClick for either whole view / form or any controls to let us easily add our event handler. But a fact should be known is that: all such events don't exist on Windows OS! The only primitive events related to mouse should be: LButton_down, LButton_up, RButton_Down, RButton_up like. For example:
a left mouse click event should be composed of: LButton_Down + LButton_Click + LButton_Up.
b. double click event should be composed of: LButton_Down + LButton_Up + LButton_Down + LButton_doubleClick + LButton_Up
(Above is not that exact, just use it to illustrate the real world of event)
Take the tricky application event handling for example (it may be a MFC application which internally uses managed code to fire and finally handle events):
0. User click in the application window area.
1. MFC View will receive a LButton_Down + LButton_Click + LButton_Up event.
2. MyCView will use its interopView which is written by C++/CLI to get the managed application written by C# to fire the event to managed code:
InteropView -> application -> eventManager -> FireMouseEvent().
Note: as we can't receive MFC wrapped event like Button_click, Button_doubleClick while just primitive events, so we need to judge by ourselves whether it's a real click or double click.