diff --git a/HandyControl/Tools/Helper/ExternDllHelper.cs b/HandyControl/Tools/Helper/ExternDllHelper.cs
index 345abe7a..77a55d5f 100644
--- a/HandyControl/Tools/Helper/ExternDllHelper.cs
+++ b/HandyControl/Tools/Helper/ExternDllHelper.cs
@@ -19,6 +19,8 @@ namespace HandyControl.Tools
 
         private const string Shell32 = "shell32.dll";
 
+        public delegate IntPtr WndProc(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);
+
         [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
         public class NOTIFYICONDATA
         {
@@ -40,6 +42,21 @@ namespace HandyControl.Tools
             public int dwInfoFlags;
         }
 
+        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
+        public class WNDCLASS_D
+        {
+            public int style;
+            public WndProc lpfnWndProc;
+            public int cbClsExtra = 0;
+            public int cbWndExtra = 0;
+            public IntPtr hInstance = IntPtr.Zero;
+            public IntPtr hIcon = IntPtr.Zero;
+            public IntPtr hCursor = IntPtr.Zero;
+            public IntPtr hbrBackground = IntPtr.Zero;
+            public string lpszMenuName = null;
+            public string lpszClassName = null;
+        }
+
         [DllImport(Shell32, CharSet = CharSet.Auto)]
         [ResourceExposure(ResourceScope.None)]
         public static extern int Shell_NotifyIcon(int message, NOTIFYICONDATA pnid);
diff --git a/HandyControlDemo/HandyControlDemo.csproj b/HandyControlDemo/HandyControlDemo.csproj
index 9c659dd1..4231f0f6 100644
--- a/HandyControlDemo/HandyControlDemo.csproj
+++ b/HandyControlDemo/HandyControlDemo.csproj
@@ -189,6 +189,7 @@
     </Compile>
     <Compile Include="UserControl\Controls\NotifyIconDemoCtl.xaml.cs">
       <DependentUpon>NotifyIconDemoCtl.xaml</DependentUpon>
+    </Compile>
     <Compile Include="UserControl\Controls\GravatarDemoCtl.xaml.cs">
       <DependentUpon>GravatarDemoCtl.xaml</DependentUpon>
     </Compile>