添加项目文件。

Fluent.Ribbon/Fluent.Ribbon.Tests/Helper/UIHelper.cs

@@ -0,0 +1,18 @@
+namespace Fluent.Tests.Helper
+{
+    using System;
+    using System.Windows.Threading;
+
+    public static class UIHelper
+    {
+        public static void DoEvents()
+        {
+            Dispatcher.CurrentDispatcher.DoEvents();
+        }
+
+        public static void DoEvents(this Dispatcher dispatcher)
+        {
+            dispatcher.Invoke(DispatcherPriority.Background, new Action(() => { }));
+        }
+    }
+}