How can WPF objects deriving from Freezable be frozen in XAML?

Question

Many types in WPF derive from Freezable. It provides immutability to mutable POCO objects and allows for improved performance in certain situations.

So

Answer 1

To freeze a Freezable object declared in markup, you use the Freeze attribute defined in XML namespace http://schemas.microsoft.com/winfx/2006/xaml/presentation/options.

In the following example, a SolidColorBrush is declared as a page resource and frozen. It is then used to set the background of a button.

  
    
    
  

  
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Source: Freezable Objects Overview