custom controls inheriting from telerik base controls

[Rahul]

Custom Controls:
public class CustomGridView : RadGridView
    {
        public CustomGridView()
        {
        }

    }
  public class RadGridViewCommands
    {

    }


<framework:CustomGridView x:Name="gvCustomerOrder" ItemsSource="{Binding Orders}"
               CanUserDeleteRows="{Binding IsChecked, Mode=TwoWay, ElementName=CanUserDeleteRowsCheckBox}"
               IsReadOnly="{Binding IsChecked, Mode=TwoWay, ElementName=IsReadOnlyCheckBox}"
               SelectionMode="Extended" VerticalAlignment="Stretch" AutoGenerateColumns="False">
                <framework:CustomGridView.Columns>
                    <framework:CustomGridViewToggleRowDetailsColumn/>
                    <framework:CustomGridViewSelectColumn x:Name="gvcSelect"/>
                    <framework:CustomGridViewDataColumn DataMemberBinding="{Binding Name" Header="S.no" />
                </framework:RTPOGridView.Columns>
 </framework:RTPOGridView>

<Button Content=" Delete" Style="{StaticResource GreyButtonStyle}" Command="framework:RadGridViewCommands.Delete" CommandTarget="{Binding ElementName=gvCustomerOrder}"/>


But In Run Time it gives an Error:
'Provide value on 'System.Windows.Baml2006.TypeConverterMarkupExtension' threw an exception.' Line number '141' and line position '60'

Hi,
We are using a custom controls inheriting from telerik base controls.
E.g. In case of datagrid,(Please find attched code Block), Command property is not accesible. It gives an Error.
We use a MVVM Pattern.
Please help on this.

[Rahul]

Issue is resolved. Its because of reference could not found in view load.