selectedItem return null after RadPane re-docking

[Felix]

Hi,

I have a RadGridView in a radpane, selectedItem return correctly, but after the radpane undocked, or docking again after undocked, the always selectedItem return null which I used for DragAndDrop. Anthing wrong or what should I do to get selectedItem return correct value? here is code:
<telerik:RadGridView
                    x:Name="itemView"
                    ItemsSource="{Binding AvailableItems}"
                    SelectedItem="{Binding SelectedAvailableItem}"
                    SelectionMode="Extended"
                    SelectionUnit="FullRow"
                    IsReadOnly="True"
                    CanUserSelect="True"
                    AllowDrop="True"
                    AutoGenerateColumns="False"
                    IsFilteringAllowed="False"
                    RowIndicatorVisibility="Collapsed"
                    Grid.Column="0"
                    Grid.Row="1">
                  
                  <telerik:RadGridView.RowStyle>
                      <Style TargetType="telerik:GridViewRow">
                       <Setter Property="telerik:RadDragAndDropManager.AllowDrag"  Value="True" />
                      <EventSetter Event="Control.RequestBringIntoView" Handler="RadGridView_RequestBringIntoView"/>
                    </Style>
                  </telerik:RadGridView.RowStyle>
               </teleric.RadGridView>

in C#
  RadDragAndDropManager.AddDragQueryHandler(itemView, OnGridViewDragQuery);

private void OnGridViewDragQuery(object sender, DragDropQueryEventArgs e)
    {
      try
      {
        if (sender is RadGridView)
        {
          RadGridView gridView = sender as RadGridView;
          IList selectedItems = gridView.SelectedItems.ToList();
          e.QueryResult = selectedItems.Count > 0;
          e.Options.Payload = selectedItems;
        }
        else
        {
          e.QueryResult = true;
        }
      }
      catch (Exception)
      {
      }
      finally
      {
        e.Handled = true;
      }
    }

After undocking or docking again(data may rebinded), when drag a item in gridview, above gridView.SelectedItems in OnGridViewDragQuery() return null.

Thanks
Felix

[Dimitrina]

Hello Felix,

The SelectedItem would be not preserved if the DataContent is lost on re-docking. To ensure this you should set a DataContext for the pane.

How does this work for you?

Regards,
Didie
Telerik

[Felix]

Hi Didie,

Thanks for your reply.
There is stackPanel in RadPane, the RadGridView(itemView) is which I want to drag, after re-docking, it is ok if pre-selection is gone but reselect is return null as in the first post.  I am not sure how to set DataContext for the pane. can I get an example?

Thanks and best regards,
Felix

[Dimitrina]

Hello,

I am not sure how have you defined your panes.
Still, a sample code would be similar to:

<telerik:RadPane Title="Description"
           DataContext="{Binding ElementName=radDocking1, Path=DataContext}">

Regards,
Didie
Telerik

[Felix]

Hi Didie,

Thanks for your reply. I tried but doesn't work.

Here I attached code related to it. it looks a bit complicated, thanks for a lot for your help and support.

<Grid>
  <Grid.Resources ...>

  <telerikDocking:RadDocking
        x:Name="myDocker"
        Grid.Row="0" Grid.Column="0" >

      <telerikDocking:RadDocking.DocumentHost >
        <telerikDocking:RadSplitContainer  
            Orientation="Vertical"
            InitialPosition="DockedRight">
          <telerikDocking:RadPaneGroup x:Name="Group2">
            <telerikDocking:RadDocumentPane
                Header="DocPane"
                CanFloat="False"
                CanUserClose="False"
                CanUserPin="False"
                CanDockInDocumentHost="False"
                PaneHeaderVisibility="Collapsed"
                ContextMenuTemplate="{x:Null}"
                Visibility="{Binding DocumentPaneHeader, Mode=OneTime}">
                <Grid.Column="0" Grid.Row="0" >
              <Grid .../>    
            </telerikDocking:RadDocumentPane>
        </telerikDocking:RadSplitContainer>
      </telerikDocking:RadDocking.DocumentHost>
    
      <telerik:RadSplitContainer Name="LeftContainer"
                                   Orientation="Vertical"
                                   InitialPosition="DockedLeft">
          <telerik:RadPaneGroup x:Name="Group1" >
            <telerik:RadPane
              CanFloat="True"
              CanUserClose="False"
              CanUserPin="True"
              CanDockInDocumentHost="False"
              IsSelected="{Binding Path=SelectedItemType, Mode=OneWay,
                                   Converter={StaticResource protocolTypeToBoolConverter}, ConverterParameter={x:Static Helpers:ItemType.Type1}}">

            <telerik:RadPane.Header>
              <StackPanel Orientation="Horizontal">
                <Image .../>
                <TextBlock
                  Text="Items"
                  VerticalAlignment="Center"/>
              </StackPanel>
            </telerik:RadPane.Header>

            <telerik:RadPane.TitleTemplate>
                <DataTemplate>
                  <Grid>
                    <Grid.ColumnDefinitions>
                      <ColumnDefinition Width="Auto" />
                      <ColumnDefinition Width="*"/>
                      <ColumnDefinition Width="40"/>
                  </Grid.ColumnDefinitions>

                  <StackPanel
                    Grid.Column="0"
                    Orientation="Horizontal">
                    <Image ...>
                    <TextBlock
                      Text="Items"
                      VerticalAlignment="Center"/>
                  </StackPanel>

                  <telerik:RadButton
                     Grid.Column="1"
                     Width="18"
                     Height="18"
                     Margin="0,0,5,0"
                     HorizontalAlignment="Right"
                     Command="{Binding RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type telerik:RadTabControl}}, Path=DataContext.AddItemCommand}"
                     CommandParameter="{Binding}"
                     ToolTip="Add sensor to graph">
                    <Grid>
                      <Image Source="/Images/Add.ico"
                               HorizontalAlignment="Stretch"
                               VerticalAlignment="Stretch"/>
                    </Grid>
                  </telerik:RadButton>

          <Grid Grid.Column="2"... >
         </Grid>
                </DataTemplate>
              </telerik:RadPane.TitleTemplate>

          <Grid Grid.Column="0" Grid.Row="0">
        <...>
          <Grid Grid.Column="{Binding Path=ColumnEquipment}"
                      Grid.Row="{Binding Path=RowEquipment}"
                      Grid.ColumnSpan="{Binding Path=ColumnSpanEquipment}"
                      Grid.RowSpan="{Binding Path=RowSpanEquipment}">
        <telerik:RadDataFilter .../>
        <telerik:RadGridView .../>
              </Grid>
              <GridSplitter.../>
              <GridSplitter.../>
        
              <Grid Grid.Column="{Binding Path=ColumnSensorProtocol}"
                      Grid.Row="{Binding Path=RowSensorProtocol}"
                      Grid.ColumnSpan="{Binding Path=ColumnSpanSensorProtocol}"
                      Grid.RowSpan="{Binding Path=RowSpanSensorProtocol}">
                  <Grid.RowDefinitions .../>
                  <telerik:RadDataFilter .../>

          <telerik:RadGridView
                    x:Name="itemView"
                    ItemsSource="{Binding AvailableItems}"
                    SelectedItem="{Binding SelectedAvailableItem}"
                    SelectionMode="Extended"
                    SelectionUnit="FullRow"
                    IsReadOnly="True"
                    CanUserSelect="True"
                    AllowDrop="True"
                    AutoGenerateColumns="False"
                    IsFilteringAllowed="False"
                    RowIndicatorVisibility="Collapsed"
                    Grid.Column="0"
                    Grid.Row="1">
                  
                    <telerik:RadGridView.RowStyle>
                      <Style TargetType="telerik:GridViewRow">
                       <Setter Property="telerik:RadDragAndDropManager.AllowDrag"  Value="True" />
                      <EventSetter Event="Control.RequestBringIntoView" Handler="RadGridView_RequestBringIntoView"/>
                     </Style>
                    </telerik:RadGridView.RowStyle>
                  </teleric.RadGridView>
              </Grid>
          <Grid .../>
      </Grid>
        </telerik:RadPane>        

    <telerik:RadPane.../>

     </telerik:RadPaneGroup>
   </telerik:RadSplitContainer>
 </telerikDocking:RadDocking>
</Grid>

Best regards
Felix

[Dimitrina]

Hi Felix,

I checked the xaml code you shared and it seems you have not explicitly set the DataContext for your RadPane. Would you please try setting it as I suggested?

Regards,
Didie
Telerik

[Felix]

Hi Diedie,

It is works as you suggested, after set
<telerik:RadPane Title="Description"
           DataContext="{Binding ElementName=myDocker, Path=DataContext}">

Thanks,
Felix

[Dimitrina]

Hi Felix,

I am glad to hear that!

Regards,
Didie
Telerik