如何使用 WPF 将不同的自定义主题（资源字典）应用于整个应用程序？

Question

我想动态更改整个应用程序的自定义主题。主题以资源字典的形式呈现，称为 ExpressionDark.xaml 和 ExpressionLight.xaml（从 Codeplex 下载）。我正在使用组合框来选择合适的主题。主题更改发生在 SelectionChanged 事件中。代码如下：

private void themesComboBox_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
ResourceDictionary resourceDictionary = new ResourceDictionary();

    int theme = ((ComboBox)sender).SelectedIndex;

    switch (theme)
    {
    case (int)Themes.Dark:
                resourceDictionary = Application.LoadComponent(
                new Uri(@"Themes\ExpressionDark.xaml",
                UriKind.Relative)) as ResourceDictionary;
                break;
            case (int)Themes.Light:
                resourceDictionary = Application.LoadComponent(
                new Uri(@"Themes\ExpressionLight.xaml",
                UriKind.Relative)) as ResourceDictionary;
                break;
            default:
                break;
    }

Application.Current.Resources = resourceDictionary;
}

这适用于当前窗口，但是当我运行另一个应用程序窗口的实例时，会发生 XamlParseException。

Answer 1

ResourceDictionary skin = new ResourceDictionary();
skin.Source = new Uri("Themes\\ExpressionLight.xaml", UriKind.Relative);
Application.Current.Resources.MergedDictionaries.Clear();
Application.Current.Resources.MergedDictionaries.Add(skin);