TextBlock binding to selected DataGrid Element

Question

Does anyone know how to dynamically set the ElementName for textblock.text binding?

I have two Datagrids that have the same information but the second DataGrid is just a filter of the same datasource, but what I want is to bind text of a textblock to the selected item depending if the item was clicked in the main datagrid or the secondary datagrid.

I have the below code to bind the textblock to one datagrid but I would also like the same to happen if the user clicked an item in the secondDataGrid.

Is this possible?

<TextBlock Margin="29,0" Text="{Binding SelectedItem.Name, ElementName=MainDataGrid}"

Answer 1

It is possible, though I don't think this is the proper solution.

You can handle one of the DataGrids' events in the code-behind, where in the handler you can write the following code:

BindingOperations.SetBinding(textBlock, TextBlock.TextProperty,
                             new Binding("SelectedItem.Name")
                             {
                                 ElementName = "DataGrid1"
                             });

Basically you reset the Binding on the TextBlock's Text property with this code, where:

• textBlock is the name of your TextBlock;

• with TextBlock.TextProperty you define that you want to work with the Text property on the TextBlock;

• The third paramter is the new Binding itself. The constructor takes the Path of the Binding and then in the "body" I set the ElementName.

If DataGrid1 fires the event you set the ElementName to that DataGrid's name, if DataGrid2 fires the event then you set the ElementName to the second DataGrid's name.

SelectionChanged can be a good event to handle on both DataGrid, but if you want the TextBlock to update when you selected and element in the first then select another one in the second and then click back to the first element to update then you need to handle the GotFocus event as well. Play a little bit with it and you will see what I mean.

My working example:

private void SetBindingOnTextBlock(string elementName)
{
    BindingOperations.SetBinding(textBlock, TextBlock.TextProperty, new Binding("SelectedItem.Name")
    {
        ElementName = elementName
    });
}

private void DataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    SetBindingOnTextBlock("DataGrid1");
}

private void DataGrid_SelectionChanged_1(object sender, SelectionChangedEventArgs e)
{
    SetBindingOnTextBlock("DataGrid2");
}

private void DataGrid1_GotFocus(object sender, RoutedEventArgs e)
{
    SetBindingOnTextBlock("DataGrid1");
}

private void DataGrid2_GotFocus(object sender, RoutedEventArgs e)
{
    SetBindingOnTextBlock("DataGrid2");
}

UPDATE 1:

Set

IsSynchronizedWithCurrentItem="True"

on the DataGrids and it may solve your problem if ItemsSources are the same. (Not sure if this is what @dkozl meant) Originally I assumed that they are different.