添加项目文件。

MSDevTool/Converters/NullToStringConverter.cs

@@ -0,0 +1,22 @@
+
+using System;
+using System.Globalization;
+using System.Windows.Data;
+
+
+namespace MSDevTool.Converters
+{
+    //用于Null值
+    public class NullToStringConverter : IValueConverter
+    {
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            return value ?? "<null>";
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            throw new NotImplementedException();
+        }
+    }
+}