Added member group picker value converter

src/Umbraco.Core/PropertyEditors/ValueConverters/MemberGroupPickerValueConverter.cs

@@ -0,0 +1,29 @@
+using System;
+using Umbraco.Core.Models.PublishedContent;
+
+namespace Umbraco.Core.PropertyEditors.ValueConverters
+{
+    public class MemberGroupPickerValueConverter : PropertyValueConverterBase, IPropertyValueConverterMeta
+    {
+        public override bool IsConverter(PublishedPropertyType propertyType)
+        {
+            return propertyType.PropertyEditorAlias.InvariantEquals(Constants.PropertyEditors.MemberGroupPickerAlias);
+        }
+
+        public override object ConvertDataToSource(PublishedPropertyType propertyType, object source, bool preview)
+        {
+            return source == null ? string.Empty : source.ToString();
+        }
+
+        public Type GetPropertyValueType(PublishedPropertyType propertyType)
+        {
+            return typeof(string);
+        }
+
+        public PropertyCacheLevel GetPropertyCacheLevel(PublishedPropertyType propertyType,
+                                                        PropertyCacheValue cacheValue)
+        {
+            return PropertyCacheLevel.Content;
+        }
+    }
+}

src/Umbraco.Core/Umbraco.Core.csproj

@@ -507,6 +507,7 @@
     <Compile Include="PropertyEditors\ValueConverters\DecimalValueConverter.cs" />
     <Compile Include="PropertyEditors\ValueConverters\LabelValueConverter.cs" />
     <Compile Include="PropertyEditors\ValueConverters\ImageCropperValueConverter.cs" />
+    <Compile Include="PropertyEditors\ValueConverters\MemberGroupPickerValueConverter.cs" />
     <Compile Include="PublishedContentTypeConverter.cs" />
     <Compile Include="Publishing\UnPublishedStatusType.cs" />
     <Compile Include="Publishing\UnPublishStatus.cs" />