port from perforce

hgplus/bliss/Tweaky/ViewModelBase.cs

@@ -0,0 +1,24 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace Tweaky
+{
+    public class ViewModelBase : INotifyPropertyChanged
+    {
+        public ViewModelBase()
+        {
+        }
+
+        public void RaisePropertyChanged(string propertyName)
+        {
+            if (PropertyChanged != null)
+                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
+        }
+
+        public event PropertyChangedEventHandler PropertyChanged;
+    }
+}