write(this); //not that

While reviewing some XAML a few days ago, I ran across this:

<Button Margin="1, 1, 1, 1" ... />

This XAML respectively sets the left, top, right and bottom margins of  the button element to 1.  While this technically works, WPF provides a handy shortcut for setting all margins to the same value:

<Button Margin="1" ... />

If you only provide one value, WPF will assume that you want to set all margins to 1.  Check this out:

<Button Margin="1, 2" ... />

This time, we’re setting the left and right margins to 1 and the top and bottom margins to 2.

I rarely find myself needing to set different values for the left, top, right and bottom margins for a given user interface element in WPF.  If you only need to set one margin, you still need to use the original syntax.  For example, if I was setting only the left margin to 1, I would have to do something like this:

<Button Margin="1, 0, 0, 0" ... />

Note that these syntax rules apply to the Padding property as well.  After wrestling with CSS for years, the layout model in WPF is a welcome breath of fresh air.