One of the best uses for markup extensions is for easier usage of IValueConverter. In the sample below BoolToVisibilityConverter is a value converter but since it's instance independent it can be used without the normal hasles of a value converter with the help of markup extension.
In XAML just use...
There are four predefined markup extensions in XAML:
x:Type supplies the Type object for the named type. This facility is used most frequently in styles and templates.
<object property="{x:Type prefix:typeNameValue}" .../>
x:Static produces static values. The values come from va...