FrameworkElements have simple
Width properties (of type
double), and they also have
MaxWidth properties that can be used to specify a range of acceptable values. Any or all of these can be easily set on elements in procedural code or in XAML.
An element naturally stays as small as possible, so if you use
MinWidth, it is rendered at that height/width unless its content forces it to grow. In addition, that growth can be limited by using
MaxWidth (as long as these values are larger than their
Min counterparts). When using an explicit
Width at the same time as their
Width take precedence as long as they are ...