IDropSource::QueryContinueDrag

Determines whether a drag-and-drop operation should be continued, canceled, or completed. You do not call this method directly. The OLE DoDragDrop function calls this method during a drag-and-drop operation.

HRESULT QueryContinueDrag(

BOOL fEscapePressed,	//Status of escape key since previous call
DWORD grfKeyState	//Current state of keyboard modifier keys
);

Parameters

fEscapePressed

[in] Specifies whether the Esc key has been pressed since the previous call to IDropSource::QueryContinueDrag or to DoDragDrop if this is the first call to QueryContinueDrag. A TRUE value indicates the end user has pressed the escape key; a FALSE value indicates it has not been pressed.

grfKeyState

[in] Current state of the keyboard modifier keys on the keyboard. Valid values can be a combination of any of the flags MK_CONTROL, MK_SHIFT, MK_ALT, MK_BUTTON, MK_LBUTTON, MK_MBUTTON, and MK_RBUTTON.

Return Values

This method supports the standard return values E_UNEXPECTED and E_OUTOFMEMORY, as well as the following:

S_OK

The drag operation should continue. This result occurs if no errors are detected, the mouse button starting the drag-and-drop operation has not been released, and the Esc key has not been detected.

DRAGDROP_S_DROP

The drop operation should occur completing the drag operation. This result occurs if grfKeyState indicates that the key that started the drag-and-drop operation has been released.

DRAGDROP_S_CANCEL

The drag operation should be canceled with no drop operation occurring. This result occurs if fEscapePressed is TRUE, indicating the Esc key has been pressed.

Remarks

The DoDragDrop function calls IDropSource::QueryContinueDrag whenever it detects a change in the keyboard or mouse button state during a drag-and-drop operation. IDropSource::QueryContinueDrag must determine whether the drag-and-drop operation should be continued, canceled, or completed based on the contents of the parameters grfKeyState and fEscapePressed.

See Also

DoDragDrop