在运行时更改资源字典

Question

我在我的 wpf 中使用 Material Design。我在运行时更改主题（浅色/深色）。

<materialDesign:DialogHost Identifier="RootDialog">
  <materialDesign:DialogHost.Resources>
    <Style TargetType="materialDesign:Card" BasedOn="{StaticResource {x:Type materialDesign:Card}}">
        <Style.Resources>
            <ResourceDictionary>
                <ResourceDictionary.MergedDictionaries>
                    <ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.dark.xaml" />
                </ResourceDictionary.MergedDictionaries>
            </ResourceDictionary>
        </Style.Resources>
        <Setter Property="Background" Value="{DynamicResource MaterialDesignCardBackground}" />
    </Style>
  </materialDesign:DialogHost.Resources>
  <Grid>
      <!--some code-->
  </Grid>
</materialDesign:DialogHost>

我想在运行时将资源字典的来源更改为

pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.light.xaml

我该怎么做？

Answer 1

在 App.xaml 中定义您的资源字典应用范围

<Application.Resources>
        <ResourceDictionary>
            <ResourceDictionary.MergedDictionaries>
                <!-- This is the default theme (useful for Designing)-->
                <ResourceDictionary Source="pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.dark.xaml"/>
            </ResourceDictionary.MergedDictionaries>
        </ResourceDictionary>
    </Application.Resources>

在后面的代码中更改主题。

public Skin ChangeSkin()
        {
            // you might want to have some logic here to keep switching
 ApplyResources("pack://application:,,,/MaterialDesignThemes.Wpf;component/Themes/MaterialDesignTheme.light.xaml")
        }

private void ApplyResources(string src)
        {
            App a = App.Current as App;
            var dict = new ResourceDictionary() { Source = new Uri(src, UriKind.Relative) };
            foreach (var mergeDict in dict.MergedDictionaries)
            {
                a.Resources.MergedDictionaries.Add(mergeDict);
            }

            foreach (var key in dict.Keys)
            {
                a.Resources[key] = dict[key];
            }
        }