DataGridTemplateColumn BeginEdit on selection

Question

I subclassed DataGridTemplateColumn to define a custom column type. I use the following code to initialize the edit mode.

    protected override object PrepareCellForEdit(
        FrameworkElement editingElement, RoutedEventArgs editingEventArgs)
    {
        editingElement.MoveFocus(
            new TraversalRequest(FocusNavigationDirection.First));
        return base.PrepareCellForEdit(editingElement, editingEventArgs);
    }

    private void MyTextControlGotFocus(object sender, RoutedEventArgs e)
    {
        var control = sender as MyTextControl;
        if (control != null)
        {
            control.SelectAll();
        }            
    }

The problem is that PrepareCellForEdit gets only called after I 1) clicked into the cell and 2) clicked again to enter edit mode.

With DataGridTextColumn I can select the cell and type in some text to immediately enter edit mode without clicking again. I want the same behaviour for my column type.

The question is, how can I handle a KeyDown event on the cell to call DataGridOwner.BeginEdit in my DataGridTemplateColumn class. I tried to add a PreviewKeyDown handler to the control inside the CellTemplate but the event does not get fired.

Answer 1

I finally came up with this soultion:

<DataGrid ItemsSource="{Binding Persons}">
  <DataGrid.Columns>
    <DataGridTemplateColumn Header="C1">
      <DataGridTemplateColumn.CellTemplate>
        <DataTemplate>
          <TextBlock Text="{Binding Name}"/>
        </DataTemplate>
      </DataGridTemplateColumn.CellTemplate>
      <DataGridTemplateColumn.CellEditingTemplate>
        <DataTemplate>
          <TextBox Text="{Binding Name}" />
        </DataTemplate>
      </DataGridTemplateColumn.CellEditingTemplate>
    </DataGridTemplateColumn>
  </DataGrid.Columns>
  <DataGrid.CellStyle>
    <Style TargetType="DataGridCell">
      <Setter Property="IsTabStop" Value="False" />
      <Setter Property="Focusable" Value="False" />
      <Style.Triggers>
        <Trigger Property="IsSelected" Value="True">
          <Setter Property="IsEditing" Value="True" />
        </Trigger>
      </Style.Triggers>
    </Style>
  </DataGrid.CellStyle>
</DataGrid>

The important part is Focusable=False (don't know why). Otherwise the IsSelected trigger works only for the first selection.