Add theme menu item

ILSpy/Commands/ILSpyCommands.cs

@@ -24,6 +24,7 @@ using System.Threading.Tasks;
 using System.Windows.Input;
 
 using ICSharpCode.ILSpy.Analyzers;
+using ICSharpCode.ILSpy.Commands;
 
 namespace ICSharpCode.ILSpy
 {
@@ -31,5 +32,6 @@ namespace ICSharpCode.ILSpy
 	{
 		public static readonly AnalyzeCommand Analyze = new AnalyzeCommand();
 		public static readonly ManageAssemblyListsCommand ManageAssemblyListsCommand = new ManageAssemblyListsCommand();
+		public static readonly SetThemeCommand SetTheme = new SetThemeCommand();
 	}
 }

ILSpy/Commands/SetThemeCommand.cs

@@ -0,0 +1,11 @@
+namespace ICSharpCode.ILSpy.Commands
+{
+	public class SetThemeCommand : SimpleCommand
+	{
+		public override void Execute(object parameter)
+		{
+			if (parameter is string theme)
+				MainWindow.Instance.SessionSettings.Theme = theme;
+		}
+	}
+}

ILSpy/MainWindow.xaml

@@ -20,6 +20,7 @@
 	xmlns:styles="urn:TomsToolbox.Wpf.Styles"
 	xmlns:b="http://schemas.microsoft.com/xaml/behaviors"
 	xmlns:themes="clr-namespace:ICSharpCode.ILSpy.Themes"
+	xmlns:toms="urn:TomsToolbox"
 	d:DataContext="{d:DesignInstance local:MainWindowViewModel}"
 >
 	<Window.Resources>
@@ -138,6 +139,23 @@
 				<MenuItem Header="{x:Static properties:Resources.Show_internalTypesMembers}" IsCheckable="True" IsChecked="{Binding Workspace.ActiveTabPage.FilterSettings.ApiVisPublicAndInternal}" />
 				<MenuItem Header="{x:Static properties:Resources.Show_allTypesAndMembers}" IsCheckable="True" IsChecked="{Binding Workspace.ActiveTabPage.FilterSettings.ApiVisAll}" />
 				<Separator/>
+				<MenuItem Header="{x:Static properties:Resources.Theme}" ItemsSource="{x:Static themes:ThemeManager.AllThemes}">
+					<MenuItem.ItemContainerStyle>
+						<Style TargetType="{x:Type MenuItem}" BasedOn="{StaticResource {x:Type MenuItem}}">
+							<Setter Property="Command" Value="{x:Static local:ILSpyCommands.SetTheme}" />
+							<Setter Property="CommandParameter" Value="{Binding}" />
+							<Setter Property="IsCheckable" Value="True" /> <!-- Required by AvalonDock's MenuItem style to show the checkmark -->
+							<Setter Property="IsChecked">
+								<Setter.Value>
+									<MultiBinding Converter="{x:Static toms:BinaryOperationConverter.Equality}" Mode="OneWay">
+										<Binding />
+										<Binding RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type local:MainWindow}}" Path="SessionSettings.Theme" />
+									</MultiBinding>
+								</Setter.Value>
+							</Setter>
+						</Style>
+					</MenuItem.ItemContainerStyle>
+				</MenuItem>
 				<MenuItem Header="{x:Static properties:Resources.UILanguage}">
 					<MenuItem Header="{x:Static properties:Resources.UILanguage_System}" IsCheckable="True" IsChecked="{Binding SessionSettings.CurrentCulture, Converter={StaticResource cultureSelectionConverter}, ConverterParameter={x:Null}}" />
 					<MenuItem Header="English" IsCheckable="True" IsChecked="{Binding SessionSettings.CurrentCulture, Converter={StaticResource cultureSelectionConverter}, ConverterParameter=en-US}" />