<telerik:RadGridView x:Name="gridView"

ShowGroupPanel="False" IsFilteringAllowed="False" AutoGenerateColumns="False"

ItemsSource="{Binding PmodCollection}"

AddingNewDataItem="gridView_AddingNewDataItem" >

<telerik:RadGridView.Columns>

<telerik:GridViewDataColumn Header="Test" DataMemberBinding="{Binding Test}" />

<telerik:GridViewComboBoxColumn UniqueName="columnDescriptor" Header="Descriptor"

DataMemberBinding="{Binding SimpleObject}" DisplayMemberPath="Descriptor"

ItemsSource="{Binding SimpleObjChoiceList}"/>

</telerik:RadGridView.Columns>

</telerik:RadGridView>

public partial class Window1 : Window

{

public Window1()

{

InitializeComponent();

this.DataContext = new DataContext();

}

private void gridView_AddingNewDataItem(object sender, GridViewAddingNewEventArgs e)

{

e.NewObject = new SimpleObjectPMod();

}

}

class DataContext

{

private List<SimpleObject> simpleObjs;

private ObservableCollection<SimpleObjectPMod> pmodCollection;

public DataContext()

{

simpleObjs = new List<SimpleObject>();

simpleObjs.Add(new SimpleObject() { Descriptor = "bla" });

simpleObjs.Add(new SimpleObject() { Descriptor = "fasel" });

pmodCollection = new ObservableCollection<SimpleObjectPMod>();

}

public List<SimpleObject> SimpleObjChoiceList

{

get { return simpleObjs; }

}

public ObservableCollection<SimpleObjectPMod> PmodCollection

{

get { return pmodCollection; }

}

}

class SimpleObjectPMod

{

public string Test

{

get; set;

}

public SimpleObject SimpleObject

{

get; set;

}

}

class SimpleObject : ICustomTypeDescriptor
{
        public string Descriptor
        {
            get; set;
        }

        #region Implementation of ICustomTypeDescriptor
        public AttributeCollection GetAttributes()
        {
            return TypeDescriptor.GetAttributes(this, true);
        }
        public string GetClassName()
        {
            return TypeDescriptor.GetClassName(this, true);
        }
        public string GetComponentName()
        {
            return TypeDescriptor.GetComponentName(this, true);
        }
        public TypeConverter GetConverter()
        {
            return TypeDescriptor.GetConverter(this, true);
        }
        public EventDescriptor GetDefaultEvent()
        {
            return TypeDescriptor.GetDefaultEvent(this, true);
        }
        public PropertyDescriptor GetDefaultProperty()
        {
            return TypeDescriptor.GetDefaultProperty(this, true);
        }
        public object GetEditor(Type editorBaseType)
        {
            return TypeDescriptor.GetEditor(this, editorBaseType, true);
        }
        public EventDescriptorCollection GetEvents()
        {
            return TypeDescriptor.GetEvents(this, true);
        }
        public EventDescriptorCollection GetEvents(Attribute[] attributes)
        {
            return TypeDescriptor.GetEvents(this, attributes, true);
        }
        public PropertyDescriptorCollection GetProperties()
        {
            return GetProperties(null);
        }
        public PropertyDescriptorCollection GetProperties(Attribute[] attributes)
        {
            return TypeDescriptor.GetProperties(this, attributes, true);
        }
        public object GetPropertyOwner(PropertyDescriptor pd)
        {
            return this;
        }
        #endregion
}