Add DBus sample to read desktop appearance color scheme

src/GirCore.Libs.slnf

@@ -34,7 +34,7 @@
       "Samples\\Adw-1\\Window\\Window.csproj",
       "Samples\\GdkPixbuf-2.0\\TestLoading\\TestLoading.csproj",
       "Samples\\GdkPixbuf-2.0\\TestMemoryLeaks\\TestMemoryLeaks.csproj",
-      "Samples\\Gio-2.0\\DBusNotification\\DBusNotification.csproj",
+      "Samples\\Gio-2.0\\DBus\\DBus.csproj",
       "Samples\\Gst-1.0\\VideoPlayback\\VideoPlayback.csproj",
       "Samples\\Gtk-4.0\\AboutDialog\\AboutDialog.csproj",
       "Samples\\Gtk-4.0\\Builder\\Builder.csproj",

src/GirCore.sln

@@ -24,7 +24,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Samples", "Samples", "{1F2E
 		Samples\Directory.Build.props = Samples\Directory.Build.props
 	EndProjectSection
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DBusNotification", "Samples\Gio-2.0\DBusNotification\DBusNotification.csproj", "{48A4AF23-C232-4498-9D25-B4620ECD9325}"
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "DBus", "Samples\Gio-2.0\DBus\DBus.csproj", "{48A4AF23-C232-4498-9D25-B4620ECD9325}"
 EndProject
 Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Gst-1.0", "Libs\Gst-1.0\Gst-1.0.csproj", "{1567FD28-14D5-4161-AB66-B099E78F6FFB}"
 EndProject

src/Samples/Gio-2.0/DBusNotification/DBusNotification.csproj → src/Samples/Gio-2.0/DBus/DBus.csproj

@@ -3,6 +3,7 @@
   <PropertyGroup>
     <OutputType>Exe</OutputType>
     <TargetFramework>net6.0</TargetFramework>
+    <RootNamespace>DBus</RootNamespace>
   </PropertyGroup>
 
   <ItemGroup>

src/Samples/Gio-2.0/DBusNotification/Program.cs → src/Samples/Gio-2.0/DBus/Program.cs

@@ -5,6 +5,7 @@ internal static class Program
     private static void Main(string[] args)
     {
         Gio.Module.Initialize();
+        Sample.DBus.ReadDesktopAppearanceColorScheme();
         Sample.DBus.SendNotification();
     }
 }

src/Samples/Gio-2.0/DBus/ReadDesktopAppereanceColorScheme.cs

@@ -0,0 +1,42 @@
+using System;
+using Gio;
+using GLib;
+
+namespace Sample;
+
+public static partial class DBus
+{
+    public static void ReadDesktopAppearanceColorScheme()
+    {
+        Console.WriteLine("Press enter to read desktop appearance color scheme...");
+        Console.ReadLine();
+
+        //Portal spec: https://docs.flatpak.org/en/latest/portal-api-reference.html#gdbus-org.freedesktop.portal.Settings
+
+        var bus = DBusConnection.Get(BusType.Session);
+        using var parameters = Variant.NewTuple(new[] {
+            Variant.NewString("org.freedesktop.appearance"),
+            Variant.NewString("color-scheme"),
+        });
+
+        using Variant ret = bus.CallSync(
+            busName: "org.freedesktop.portal.Desktop",
+            objectPath: "/org/freedesktop/portal/desktop",
+            interfaceName: "org.freedesktop.portal.Settings",
+            methodName: "Read",
+            parameters: parameters,
+            replyType: VariantType.New("(v)"),
+            flags: DBusCallFlags.None,
+            timeoutMsec: 9999,
+            cancellable: null
+        );
+        var mode = ret.GetChildValue(0).GetVariant().GetVariant().GetUint32() switch
+        {
+            0 => "No Preference",
+            1 => "DarkMode",
+            2 => "LightMode",
+            _ => "Unknown"
+        };
+        Console.WriteLine("Result: " + mode);
+    }
+}