IDropSource::QueryContinueDrag - OLE Programmer's Reference

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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] Identifies the 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
S_OK

The drag operation should continue. This result occurs if no errors are detected, the mouse button starting the drag-and-rop 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.

E_OUTOFMEMORY

Out of memory.

E_UNEXPECTED

An unexpected error occurred.

Comments
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 determines 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

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