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

问题

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

So my question is, how can I freeze objects in XAML markup?

(Note that I have posted a similar but different question too).

回答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.

<Page 
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:po="http://schemas.microsoft.com/winfx/2006/xaml/presentation/options" 
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
  mc:Ignorable="po">

  <Page.Resources>
    <!-- This brush is frozen -->
    <SolidColorBrush x:Key="MyBrush" po:Freeze="True" Color="Red" />
  </Page.Resources>

  <!-- Use the frozen brush -->
  <Button Background="{StaticResource MyBrush}">Click Me</Button>

</Page>

Source: Freezable Objects Overview

回答2:

Add this to your xaml namespace declarations:

xmlns:po="http://schemas.microsoft.com/winfx/2006/xaml/presentation/options"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="po"

then, in your freezable objects, include this attribute

po:Freeze="True"

来源：https://stackoverflow.com/questions/799890/how-can-wpf-objects-deriving-from-freezable-be-frozen-in-xaml

标签

wpf

performance

xaml

freezable