Adding StackPanel in StackPanel Programmatically

Adding StackPanel in StackPanel Programmatically

I'm trying to implement a layout which is made on runtime.
layout will be divided into 2, 3, 4, ...
For example, There is a Big Box with 1 image.
If I drag and drop a image, it will be divided into two.
Like A => A | B or B | A
and If I drag&drop another image, it will be
A | | B
A | B => --| B or A | --
C | | C
simple hint will be great.