Problem when setting Header to a binding with ElementName

[Patrick]

Hello,
create a new Silverlight 5 application and replace MainPage.xaml, with:

<UserControl
  x:Class="Test_DataGrid_Binding.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:telerik="http://schemas.telerik.com/2008/xaml/presentation"
    mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480">
    <Grid Margin="5">
    <Grid.RowDefinitions>
      <RowDefinition Height="Auto" />
      <RowDefinition />
    </Grid.RowDefinitions>

    <TextBlock Name="Text"
               Text="TextBlock text" />

    <telerik:RadGridView AutoGenerateColumns="False"
                         Grid.Row="1">
      <telerik:RadGridView.Columns>
        <telerik:GridViewDataColumn DataMemberBinding="{Binding MyProperty}"
                                    Header="{Binding Text, ElementName=Text}" />
      </telerik:RadGridView.Columns>
    </telerik:RadGridView>

    </Grid>
</UserControl>

Run the application: the header of the column is empty, but should be the text of the Text TextBox.
In some more complex scenario, the header text is set to the path of the DataMemberBinding (MyProperty here)!

Patrick

[Yoan]

Hi Patrick,

 Instead of setting binding directly to the header property , please try using HeaderCellStyle. Check the following XAML:

<UserControl.Resources>
        <my:MyViewModel x:Key="MyViewModel"/>
        <DataTemplate x:Key="HeaderTemplate">
            <TextBlock Text="{Binding Text, ElementName=TextBox1}"/>
        </DataTemplate>
  </UserControl.Resources>

<telerik:GridViewDataColumn DataMemberBinding="{Binding Name}" >
   <telerik:GridViewDataColumn.HeaderCellStyle>
       <Style TargetType="telerik:GridViewHeaderCell">
           <Setter Property="ContentTemplate" Value="{StaticResource HeaderTemplate}"/>
       </Style>
    </telerik:GridViewDataColumn.HeaderCellStyle>
</telerik:GridViewDataColumn>

For your convenience I have prepared a sample project, please find it attached.

I believe this helps.


Greetings,
Yoan
the Telerik team

[Patrick]

Yoan,
it works, but with your solution I need to define a DataTemplate and the HeaderCellStyle for each column on the GridView!

The binding for the header works perfectly if we don't use the ElementName property of the binding, so it should be a bug in the RadGridView.

The final use in my case is I have a control that returns the text of a resource from the name of the resource, via a converter.
I need a control because binding directly to a static resource will lead to memory leak (the binding is never removed by Silverlight). With the control I can use the Loaded and Unloaded events to add / remove the binding. This scenarion works really well.. except for the GridView headers.

----Remove comment above----
|Note: if I define a class that descend from GridViewDataColumn, the binding work perfectly!
----------------------------------------
Patrick

[Yoan]

Hi Patrick,

Please check this troubleshooting guide for a reference.

Greetings,
Yoan
the Telerik team

[Patrick]

Yoan,
I now understand why it's not working with ElementName binding, but you  should document this as a remark in the GridViewColumn.Header property documentation.
Now I need to find another way to express that I want, because I can't have to write all this XAML code for each column (more than 1000 columns in about 40 gridview's and there are other to come...)
Patrick

[Edward]

That was what I thought, so thanks for providing a confirmation.  

However. how would you bind to both a ElementName and the DataMember of the column?

[Dimitrina]

Hello,

To Patrick: Thank you for your suggestion. We will add this remark to the API reference.
To Edward: I am not sure that I can understand your question, would you please clarify?

Regards,
Didie
the Telerik team