Function DoDragDrop 

pub unsafe fn DoDragDrop<'a, T0__: IntoParam<'a, IDataObject>, T1__: IntoParam<'a, IDropSource>>(
    pdataobj: T0__,
    pdropsource: T1__,
    dwokeffects: u32,
    pdweffect: *mut u32,
) -> ErrorCode