fixed a bug of MessageBox

src/Shared/HandyControlDemo_Shared/UserControl/Controls/WindowDemoCtl.xaml.cs

@@ -23,12 +23,12 @@ namespace HandyControlDemo.UserControl
         {
             MessageBox.Show(new MessageBoxInfo
             {
-                MessageBoxText = Properties.Langs.Lang.GrowlAsk,
+                Message = Properties.Langs.Lang.GrowlAsk,
                 Caption = Properties.Langs.Lang.Title,
                 Button = MessageBoxButton.YesNo,
                 IconBrushKey = ResourceToken.AccentBrush,
                 IconKey = ResourceToken.AskGeometry,
-                Style = ResourceHelper.GetResource<Style>("MessageBoxCustom")
+                StyleKey = "MessageBoxCustom"
             });
         }