Silverlight Drag and Drop (without a Canvas)

1
votes

I'm trying to drag and drop (slide) a Silverlight element from one part of a window to another.

I've implemented the MouseLeftButtonDown, MouseMove, and MouseLeftButtonUp event handlers on the element, but I've run into a bit of a problem.

All of the examples I've seen involve moving the element by setting the Canvas.Left and Canvas.Top properties. None of the elements I'm trying to manipulate live inside a Canvas. Is there a way to set the absolute position of the element being dragged, based on the coordinates of the mouse? Or is there a prepackaged solution to this problems somewhere that I've missed?

2
silverlightpositioning
The exact same problem I was having in my program. I had seen all kinds of tutorials involving the canvas control, but I spent hours trying to tweak it to fit the controls I was working with and didn't even work at all, but anywho, great question, and great answer - AmbiguousX

2 Answers

3
votes

All panels but Canvas use some kind of constraint to position their children. Only Canvas lets you use absolute positioning. That's why I think it is the only way to implement drag and drop .

Feel free to use a Canvas on top of your existing panel. Just remember to remove the dragged element from its original parent and put it in the Canvas (or drag some kind of copy) and do the reverse on mouse up.

0
votes

One way of achieving absolutely positioning an item inside any container, not only Canvas, is to use transformation instead of Left/Top properties. For instance, to set at Left=50 Top=80 you can modify the margin values through transformation.