WM_MBUTTONDBLCLK Overview  Group

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

WM_MBUTTONDBLCLK 

fwKeys = wParam;        // key flags 

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

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

 

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

xPos

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

Return Values

If an application processes this message, it should return zero.

Remarks

Only windows that have the CS_DBLCLKS style can receive WM_MBUTTONDBLCLK messages, which Windows generates whenever 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: WM_MBUTTONDOWN, WM_MBUTTONUP, WM_MBUTTONDBLCLK, and WM_MBUTTONUP again.

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

See Also

GetCapture, GetDoubleClickTime, MAKEPOINTS, POINTS, SetCapture, SetDoubleClickTime, WM_MBUTTONDOWN, WM_MBUTTONUP