Added dropdown list value converter

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

@@ -0,0 +1,29 @@
+using System;
+using Umbraco.Core.Models.PublishedContent;
+
+namespace Umbraco.Core.PropertyEditors.ValueConverters
+{
+    public class DropdownListValueConverter : PropertyValueConverterBase, IPropertyValueConverterMeta
+    {
+        public override bool IsConverter(PublishedPropertyType propertyType)
+        {
+            return propertyType.PropertyEditorAlias.InvariantEquals(Constants.PropertyEditors.DropDownListAlias);
+        }
+
+        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

@@ -500,6 +500,7 @@
     <Compile Include="PropertyEditors\ValueConverters\CheckboxListValueConverter.cs" />
     <Compile Include="PropertyEditors\ValueConverters\DropdownListMultipleValueConverter.cs" />
     <Compile Include="PropertyEditors\ValueConverters\DropdownListMultipleWithKeysValueConverter.cs" />
+    <Compile Include="PropertyEditors\ValueConverters\DropdownListValueConverter.cs" />
     <Compile Include="PropertyEditors\ValueConverters\EmailAddressValueConverter.cs" />
     <Compile Include="PropertyEditors\ValueConverters\GridValueConverter.cs" />
     <Compile Include="PropertyEditors\ValueConverters\DecimalValueConverter.cs" />