WM_MBUTTONDBLCLK

fwKeys = wParam; /* key flags */

xPos = LOWORD(lParam); /* horizontal position of cursor */

yPos = HIWORD(lParam); /* vertical position of cursor */

The WM_MBUTTONDBLCLK message is posted when the user double-clicks the middle mouse button while the mouse 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.

Parameters

fwKeys

Value of wParam. Indicates whether various virtual keys are down. This parameter can be any combination of the following values:

Value

Description

MK_CONTROL	Set if CTRL key is down.
MK_LBUTTON	Set if left mouse button is down.
MK_MBUTTON	Set if middle mouse button is down.
MK_RBUTTON	Set if right mouse button is down.
MK_SHIFT	Set if SHIFT key is down.

xPos

Value of the low-order word of lParam. Specifies the x-coordinate of the mouse cursor. The coordinate is relative to the upper-left corner of the client area.

yPos

Value of the high-order word of lParam. Specifies the y-coordinate of the mouse cursor. The coordinate is relative to the upper-left corner of the client area.

Return Value

An application should return zero if it processes this message.

Comments

Only windows that have the CS_DBLCLKS style can receive WM_MBUTTONDBLCLK messages. Windows generates a WM_MBUTTONDBLCLK message when the user presses, releases, and again presses the middle mouse button within the system's double-click time limit. Double-clicking the middle mouse button actually generates four messages: a WM_MBUTTONDOWN message, a WM_MBUTTONUP message, the WM_MBUTTONDBLCLK message, and another WM_MBUTTONUP message.

An application can use the MAKEPOINTS macro to convert the lParam parameter to a POINTS structure.