WM_LBUTTONDOWN top-level constant
int
const WM_LBUTTONDOWN
Posted when the user presses the left mouse button while the cursor is in the client area of a window. If the mouse is not captured, the message is posted to the window beneath the cursor. Otherwise, the message is posted to the window that has captured the mouse.
Implementation
const WM_LBUTTONDOWN = 0x0201;