Getting an error while using ColumnGroupDescriptor in RadGridView in WPF

[Vinod]

Hello Guys....I am getting an error while using ColumnGroupDescriptor in XAML,  to make a group based on some column....
if i do not use the following code in my xaml then it is working nicely and that code is:-

<telerik:RadGridView.GroupDescriptors>
                <telerik:ColumnGroupDescriptor Column="{Binding Columns[\PresentationName\], ElementName=telrikDataGrid}" SortDirection="Ascending" />
            </telerik:RadGridView.GroupDescriptors>


As i am using the above code the it showing a green underline...and showing a error as:
" NullReferenceException was thrown on "ColumnGroupDescriptor": Object reference not set to an instance of an object. " 

please guide me where i amm going wrong...please help me out ASAP.....Thank you guys...

i am also sending my project. So please find it as attachment.

Thanks!!!!!1

<Window x:Class="DataGridLoadingTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
        xmlns:local="clr-namespace:DataGridLoadingTest"
        xmlns:s="clr-namespace:System;assembly=mscorlib"
        xmlns:telerikData="clr-namespace:Telerik.Windows.Data;assembly=Telerik.Windows.Data"
        Title="MainWindow" Height="350" Width="600">

    <Window.Resources>

        <!--<src:BoolToVisiblityConverter x:Key="bool2vis"/>-->


    </Window.Resources>

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="20"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>


          <Button Grid.Row="0"  Content="LoadData" Click="LaodData_Click" HorizontalAlignment="Right"/>

        <telerik:RadGridView x:Name="telrikDataGrid" Grid.Row="1" ShowColumnFooters="True" ShowGroupFooters="True"
                                     AlternateRowBackground="Azure" AlternationCount="2" AutoGenerateColumns="False"
                                     IsReadOnly="True">


            <telerik:RadGridView.Columns>

                <telerik:GridViewDataColumn Header="ID" DataMemberBinding="{Binding PresentationID}">
                    <telerik:GridViewDataColumn.AggregateFunctions>
                        <telerik:CountFunction Caption="Total Rows"/>
                    </telerik:GridViewDataColumn.AggregateFunctions>
                </telerik:GridViewDataColumn>

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


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

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


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


                <telerik:GridViewDataColumn Header="Duration(Sec)" DataMemberBinding="{Binding Duration}">

                    <telerik:GridViewDataColumn.AggregateFunctions>
                        <telerik:SumFunction SourceFieldType="{x:Type s:Int64}" ResultFormatString="{}{0:d}" Caption="Total Duration: " SourceField="Duration"/>
                    </telerik:GridViewDataColumn.AggregateFunctions>

                </telerik:GridViewDataColumn>

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

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

            </telerik:RadGridView.Columns>

            <telerik:RadGridView.GroupDescriptors>

                <telerik:ColumnGroupDescriptor Column="{Binding Columns[\PresentationName\], ElementName=telrikDataGrid}" SortDirection="Ascending" />
            </telerik:RadGridView.GroupDescriptors>


        </telerik:RadGridView>

    </Grid>
</Window>

<Window x:Class="DataGridLoadingTest.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
        xmlns:local="clr-namespace:DataGridLoadingTest"
        xmlns:s="clr-namespace:System;assembly=mscorlib"
        xmlns:telerikData="clr-namespace:Telerik.Windows.Data;assembly=Telerik.Windows.Data"
        Title="MainWindow" Height="350" Width="600">

    <Window.Resources>

        <!--<src:BoolToVisiblityConverter x:Key="bool2vis"/>-->


    </Window.Resources>

    <Grid>
        <Grid.RowDefinitions>
            <RowDefinition Height="20"/>
            <RowDefinition Height="*"/>
        </Grid.RowDefinitions>


          <Button Grid.Row="0"  Content="LoadData" Click="LaodData_Click" HorizontalAlignment="Right"/>

        <telerik:RadGridView x:Name="telrikDataGrid" Grid.Row="1" ShowColumnFooters="True" ShowGroupFooters="True"
                                     AlternateRowBackground="Azure" AlternationCount="2" AutoGenerateColumns="False"
                                     IsReadOnly="True">


            <telerik:RadGridView.Columns>

                <telerik:GridViewDataColumn Header="ID" DataMemberBinding="{Binding PresentationID}">
                    <telerik:GridViewDataColumn.AggregateFunctions>
                        <telerik:CountFunction Caption="Total Rows"/>
                    </telerik:GridViewDataColumn.AggregateFunctions>
                </telerik:GridViewDataColumn>

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


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

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


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


                <telerik:GridViewDataColumn Header="Duration(Sec)" DataMemberBinding="{Binding Duration}">

                    <telerik:GridViewDataColumn.AggregateFunctions>
                        <telerik:SumFunction SourceFieldType="{x:Type s:Int64}" ResultFormatString="{}{0:d}" Caption="Total Duration: " SourceField="Duration"/>
                    </telerik:GridViewDataColumn.AggregateFunctions>

                </telerik:GridViewDataColumn>

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

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

            </telerik:RadGridView.Columns>

            <telerik:RadGridView.GroupDescriptors>
                <!--Here i am getting an error..i mean in the given line as " Object reference not set to an instance of an object.    "-->
                <telerik:ColumnGroupDescriptor Column="{Binding Columns[\PresentationName\], ElementName=telrikDataGrid}" SortDirection="Ascending" />
            </telerik:RadGridView.GroupDescriptors>


        </telerik:RadGridView>

    </Grid>
</Window>


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


                <telerik:GridViewDataColumn Header="Duration(Sec)" DataMemberBinding="{Binding Duration}">

                    <telerik:GridViewDataColumn.AggregateFunctions>
                        <telerik:SumFunction SourceFieldType="{x:Type s:Int64}" ResultFormatString="{}{0:d}" Caption="Total Duration: " SourceField="Duration"/>
                    </telerik:GridViewDataColumn.AggregateFunctions>

                </telerik:GridViewDataColumn>

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

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

            </telerik:RadGridView.Columns>

            <telerik:RadGridView.GroupDescriptors>

                <telerik:ColumnGroupDescriptor Column="{Binding Columns[\PresentationName\], ElementName=telrikDataGrid}" SortDirection="Ascending" />
            </telerik:RadGridView.GroupDescriptors>


        </telerik:RadGridView>

    </Grid>
</Window>

[Stephen]

I'm having the exact same problem in Silverlight. Please help.

[Vlad]

Hi,

 Unfortunately we are out of ideas what can cause this. A sample project where the problem can be reproduced will help us.

Best wishes,
Vlad
the Telerik team

[Licenses]

I have the same error!! Help

[Rossen Hristov]

Hi,

Unfortunately we are out of ideas what can cause this. A sample project where the problem can be reproduced will help us. 

All the best,
Ross
the Telerik team

[Licenses]

I solved, but using the index of the column, the column apparently can not be found by name or syntax that you indicate. (Columns [\ ColName \])

<telerik:ColumnGroupDescriptor Column="{Binding Columns[0], ElementName=Grid1}"/>

[Fredy]

Add UniqueName

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