Question

What is the best solution to check is one control located over other.

For example, I have two TextBoxes and when one TextBox is over the other I need to hide one of them.

AND i need to determine is this cotnrols overlaped before i will add them to visul tree!

Answer 1

I assume you mean you want to find out if they overlap in the Z-dimension?

Untested:

// requires System.Windows.Controls.Toolkit.dll

using System.Windows.Controls.Primitives;
// ...

Rect? rect1 = myControl1.GetBoundsRelativeTo(someParentContainer);
Rect? rect2 = myControl2.GetBoundsRelativeTo(someParentContainer);

bool areIntersecting = rect1 != null && rect2 != null
    && rect1.Value.Intersect(rect2.Value) != Rect.Empty;