Imported Upstream version 4.6.0.125

Former-commit-id: a2155e9bd80020e49e72e86c44da02a8ac0e57a4

mcs/class/referencesource/System.Web.Extensions/ui/EmptyStringExpandableObjectConverter.cs

@@ -0,0 +1,25 @@
+//------------------------------------------------------------------------------
+// <copyright file="EmptyStringExpandableObjectConverter.cs" company="Microsoft">
+//     Copyright (c) Microsoft Corporation.  All rights reserved.
+// </copyright>
+//------------------------------------------------------------------------------
+ 
+namespace System.Web.UI {
+    using System;
+    using System.ComponentModel;
+    using System.Globalization;
+
+    // Used by objects that are subproperties of Controls.  Improves the UI in the property grid by displaying
+    // nothing as the property value, instead of the fully qualified type name.
+    internal sealed class EmptyStringExpandableObjectConverter : ExpandableObjectConverter {
+        public override object ConvertTo(ITypeDescriptorContext context, CultureInfo culture, object value,
+                                         Type destinationType) {
+            if (destinationType == typeof(string)) {
+                return String.Empty;
+            }
+            else {
+                return base.ConvertTo(context, culture, value, destinationType);
+            }
+        }
+    }
+}