KeyBoard focus wpf：从其他UserControls TreeView按TAB时，将KeyBoard Focus设置为DataGrids第一行

Question

I have two UserControls One has a TreeView and another has a Button and a DataGrid .

What i am trying to achieve is when Tab on a TreeViewItem should give KeyBoard Focus to the DataGrid in second UserControl.

I have looked in to different posts but no luck. find my XAML below,

<Grid>
  <Grid.RowDefinitions>
        <RowDefinition Height="Auto" />
        <RowDefinition Height="Auto" />            
    </Grid.RowDefinitions>
   <UC:ExplorerView DataContext="{Binding ExplorerViewModel}" Grid.Row="0"/>
   <UCs:TableOfContentView DataContext="{Binding TableOfContentViewModel}" x:Name="TOCView" Grid.Row="1"/>
</Grid>

simplified XAML for the question.

I have tried to set the focus to the Second UserControl by adding event PreviewKeyDown

 private void ExplorerView_KeyDown(object sender, KeyEventArgs e)
    {
        if(e.Key == Key.Tab)
        {                
            Keyboard.Focus(TOCView);
        }
    }

But this give focus to the USerControl not to the DataGrid as i mentioned above.

Tried to Attach a Property to the DataGrid . it worked as expected but not giving focus to the first row . this thread given the input for that.

Solved :)

Created the AttachedProperty mentioned in the thread above and modified the callback method to set the focus to the DataGrids First Row like below,

  private static object OnCoerceValue(DependencyObject d, object baseValue)
    {  
        if (((DataGrid)d).HasItems)
        {
            DataGridRow row = ((DataGrid)d).ItemContainerGenerator.ContainerFromIndex(0) as DataGridRow;
            if(row !=null)
            { 
                if ((bool)baseValue)
                {
                    FocusManager.SetIsFocusScope(row, true);
                    FocusManager.SetFocusedElement(row, row);
                }
                else if (((UIElement)d).IsFocused)
                    Keyboard.ClearFocus();
            }
        }
        return ((bool)baseValue);            
    }

Please feel free to add any better solution. Thanks in Advance.

Answer 1

Created the AttachedProperty mentioned in the thread above and modified the callback method to set the focus to the DataGrids First Row like below,

  private static object OnCoerceValue(DependencyObject d, object baseValue)
    {  
        if (((DataGrid)d).HasItems)
        {
            DataGridRow row = ((DataGrid)d).ItemContainerGenerator.ContainerFromIndex(0) as DataGridRow;
            if(row !=null)
            { 
                if ((bool)baseValue)
                {
                    FocusManager.SetIsFocusScope(row, true);
                    FocusManager.SetFocusedElement(row, row);
                }
                else if (((UIElement)d).IsFocused)
                    Keyboard.ClearFocus();
            }
        }
        return ((bool)baseValue);            
    }