can new group use inherited groupdescriptor

[David Ocasio]

i am using your example code for sorting groups by an aggregate function

Public Class SortingGroupDescriptor
    Inherits groupdescriptor

    Public Overrides Function CreateGroupSortExpression(ByVal groupingExpression As System.Linq.Expressions.Expression) As System.Linq.Expressions.Expression
        If Me.AggregateFunctions.Count = 0 Then
            Return MyBase.CreateGroupSortExpression(groupingExpression)
        Else
            Return Me.AggregateFunctions(0).CreateAggregateExpression(groupingExpression)
        End If
    End Function

End Class

<telerik:RadGridView  Grid.Row="1" IsReadOnly="True" x:Name="gridInventory" AutoGenerateColumns="False" EditTriggers="None" ShowGroupFooters="False" GroupRowStyle="{StaticResource MyCustomGroupRowStyle}"  >

     <telerik:RadGridView.GroupHeaderTemplate>
         <DataTemplate>
             <Grid>
                 <Grid.ColumnDefinitions>
                     <ColumnDefinition Width="200" />
                     <ColumnDefinition Width="100" />
                     <ColumnDefinition Width="100" />
                     <ColumnDefinition Width="100" />
                     <ColumnDefinition Width="100" />
                 </Grid.ColumnDefinitions>
                 <TextBlock Text="{Binding Header}"    Grid.Column="0" Margin="4,0,0,0" TextAlignment="Left" VerticalAlignment="Center" />
                 <TextBlock Text="Extended:" Grid.Column="1" TextAlignment="Right" Margin="0,0,4,0" />
                 <TextBlock Text="{Binding AggregateResults[0].Value,StringFormat=\{0:c0\}}"   Grid.Column="2" Margin="4,0,0,0" TextAlignment="Right" VerticalAlignment="Center" />
                 <TextBlock Text="Count:" Grid.Column="3" TextAlignment="Right" Margin="0,0,4,0"  />
                 <TextBlock Text="{Binding AggregateResults[1].Value}"   Grid.Column="4" Margin="4,0,0,0" TextAlignment="Right" VerticalAlignment="Center" />
             </Grid>
         </DataTemplate>
     </telerik:RadGridView.GroupHeaderTemplate>
     <telerik:RadGridView.Columns>
         <telerik:GridViewDataColumn DataMemberBinding="{Binding CustName}" Header="Customer" UniqueName="CustName" />
         <telerik:GridViewDataColumn DataMemberBinding="{Binding Z_No}" Header="Part#" />
         <telerik:GridViewDataColumn DataMemberBinding="{Binding NameManf}" Header="Manufacturer" />
         <telerik:GridViewDataColumn DataMemberBinding="{Binding ManfNo}" Header="Manf#" />
         <telerik:GridViewDataColumn DataMemberBinding="{Binding ZDesc}" Header="Description" />
         <telerik:GridViewDataColumn DataMemberBinding="{Binding QtyOnHand}" Header="Qty"  TextAlignment="Right" />
         <telerik:GridViewDataColumn DataMemberBinding="{Binding Cost}" Header="Cost"  TextAlignment="Right" DataFormatString="{} {0:c6}" />
         <telerik:GridViewDataColumn DataMemberBinding="{Binding Extended}" Header="Extended" DataFormatString="{} {0:c0}"  TextAlignment="Right"  />
         <telerik:GridViewDataColumn Header="Customer Count" TextAlignment="Right" DataMemberBinding="{Binding custcount}" />
         <telerik:GridViewDataColumn DataMemberBinding="{Binding NameCommodity}" Header="Commodity" />
     </telerik:RadGridView.Columns>

     <telerik:RadGridView.GroupDescriptors >
         <local:SortingGroupDescriptor Member="CustName" SortDirection="Descending" >
             <local:SortingGroupDescriptor.AggregateFunctions >
                 <telerik:SumFunction SourceField="Extended"  ResultFormatString="{} {0:C0}" />
                 <telerik:CountFunction ResultFormatString="{} {0:C0}" />
             </local:SortingGroupDescriptor.AggregateFunctions>
         </local:SortingGroupDescriptor>
     </telerik:RadGridView.GroupDescriptors>
 </telerik:RadGridView>

Unfortunatly if the user removes the group i set up in xaml to choose there own group
the  type of descriptor added is not the one i indicated in xaml

so the sorting of the groups is lost

is there anyway to pass my inherited class when the group is started ...
i tried the event "grouping" but the groupdescriptor propery is readonly

thanks
dco

[Yavor Georgiev]

Hello David Ocasio,

 In the Grouping event, you can cancel the grouping operation (e.Cancel = True) so that the group descriptor in the GroupDescriptor property is not added. You then create an instance of your own IGroupDescriptor implementation and add it to the RadGridView.

Regards,
Yavor Georgiev
the Telerik team

[David Ocasio]

thanks yavor

that works
dco