What is the difference between:
HorizontalAlignment=\"Stretch\" HorizontalContentAlignment=\"Stretch\"in a
HorizontalContentAlignment and VerticalContentAlignment are used with Content Controls which apply these to its content. For example in the following code the Content Control Button will align its content(which is a string in this case and can be any arbitrary object) to center.
HorizontalAlignment and VerticalAlignment are used with child elements when these are inside a Panel. Panel will arrange its children based on these properties of child elements. In the following code the Panel (StackPanel) will align its child (Button) to right.