I feedback the question,but it is not still resolve,so when i got the old source code,
after i deal with the gridview column resize,i found the question code:
in ChromelessWindowHelper.cs file:
modify the function HandleMoving(IntPtr hwnd, IntPtr wParam, IntPtr lParam, out bool handled):
just none the following code:
//NativeMethods.CopyToRECT(position, ref currentPosition);
so it is OK! i think when coordinate transform from int type to double type and then from double type to int type,
at last,there is the offset.