添加项目文件。

Fluent.Ribbon/Fluent.Ribbon.Showcase/ViewModels/ViewModel.cs

@@ -0,0 +1,17 @@
+namespace FluentTest.ViewModels
+{
+    using System.ComponentModel;
+    using System.Runtime.CompilerServices;
+    using JetBrains.Annotations;
+
+    public class ViewModel : INotifyPropertyChanged
+    {
+        public event PropertyChangedEventHandler PropertyChanged;
+
+        [NotifyPropertyChangedInvocator]
+        protected void OnPropertyChanged([CallerMemberName] string propertyName = null)
+        {
+            this.PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+        }
+    }
+}