<!--This editor will make sure that the text entered is A, B or C (upper case)-->
<igEditors:XamTextEditor x:Name="textEditor4" InvalidValueBehavior="DisplayErrorMessage" >
<igEditors:XamTextEditor.ValueConstraint>
<igEditors:ValueConstraint>
<igEditors:ValueConstraint.Enumeration>
<x:Array Type="{x:Type system:Object}">
<system:String>A</system:String>
<system:String>B</system:String>
<system:String>C</system:String>
</x:Array>
</igEditors:ValueConstraint.Enumeration>
</igEditors:ValueConstraint>
</igEditors:XamTextEditor.ValueConstraint>
</igEditors:XamTextEditor>