WPF drag distance threshold

c#, drag-and-drop, treeview, wpf

Solution

There's a system parameter for this. If you have

Point down = {where mouse down event happened}
Point current = {position in the MouseMove eventargs}

then the mouse has moved the minimum drag distance if

Math.Abs(current.X - down.X) >= SystemParameters.MinimumHorizontalDragDistance ||
Math.Abs(current.Y - down.Y) >= SystemParameters.MinimumVerticalDragDistance

Problem

I have a program with two WPF treeviews that allow dragging and dropping between the two. The problem is, it can be annoying to open / close items on the treeviews because moving the mouse just one pixel while holding the left mouse button triggers the drag / drop functionality. Is there some way to specify how far the mouse should move before it's considered a drag / drop?

Original source