Show and focus TextBox in DataTemplate - wpf

Question

I have searched high and low, but I can't figure this one out. I am building a ListBox that has editable items. I have a DataTemplate for the ListBox.ItemTemplate that contains (among other things) a TextBlock and a TextBox. The TextBlock is always visible, and the TextBox is only visible after the user double-clicks on the TextBlock. When the user clicks another item in the list, the TextBox hides again to show the TextBlock. All of this works great. See my code:
XAML
<Window.Resources>
<local:GoalCollection x:Key="goals"/>
<DataTemplate x:Key="GoalItemTemplate" DataType="local:Goal">
<Grid>
<TextBlock Text="{Binding Title}"
MouseLeftButtonDown="TextBlock_MouseLeftButtonDown"
VerticalAlignment="Center"/>
<TextBox Name="EntryBox"
Text="{Binding Title}"
Visibility="Hidden"
BorderBrush="{x:Null}"
Padding="-2,0,0,0"
Panel.ZIndex="1"
Margin="-2,0,0,0"/>
</Grid>
</DataTemplate>
</Window.Resources>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="2*" />
</Grid.ColumnDefinitions>
<ListBox Name="GoalsList"
ItemsSource="{Binding Source={StaticResource goals}}"
HorizontalContentAlignment="Stretch"
ItemTemplate="{StaticResource GoalItemTemplate}"
SelectionChanged="GoalsList_SelectionChanged" />
</Grid>
C#
public partial class MainWindow : Window
{
GoalCollection goals;
public MainWindow()
{
InitializeComponent();
}
private childItem FindVisualChild<childItem>(DependencyObject obj)
where childItem : DependencyObject { ... }
protected override void OnInitialized(EventArgs e)
{
base.OnInitialized(e);
goals = (GoalCollection)Resources["goals"];
}
private void TextBlock_MouseLeftButtonDown(object sender,
MouseButtonEventArgs e)
{
if (e.ClickCount == 2)
{
TextBlock tblk = sender as TextBlock;
if (tblk == null)
return;
TextBox tbx = ((Grid)tblk.Parent).FindName("EntryBox") as TextBox;
if (tbx == null)
return;
tbx.Visibility = Visibility.Visible;
Keyboard.Focus(tbx);
}
}
private void GoalsList_SelectionChanged(object sender,
SelectionChangedEventArgs e)
{
ListBoxItem lbi;
ContentPresenter cp;
DataTemplate dt;
TextBox tbx;
foreach (Goal item in e.RemovedItems)
{
lbi = (ListBoxItem)GoalsList.ItemContainerGenerator.
ContainerFromItem(item);
cp = FindVisualChild<ContentPresenter>(lbi);
dt = cp.ContentTemplate;
tbx = (TextBox)dt.FindName("EntryBox", cp);
if (tbx == null)
continue;
tbx.Visibility = Visibility.Hidden;
}
}
}
The problem that I'm having is that the TextBox immediately shifts focus back to the host ListBoxItem after the double-click. An additional (third) click is required to focus on the TextBox.
Tracing through this, I have found that the TextBox does indeed receive focus. But then it immediately loses it (try adding a handler for the TextBox.LostKeyboardFocus event and step through and out of the `TextBlock_MouseLeftButtonDown()' method). Any ideas?
Thanks.

Answer 1

My guess is that the click event is bubbling up to the ListBox and it's handling it by selecting the item.
Try adding this to your Click event handler (after Keyboard.Focus(tbx);)
e.Handled = true;

Answer 2

If you want to give focus to a child element, try the FocusManager.
<DataTemplate x:Key="MyDataTemplate" DataType="ListBoxItem">
<Grid>
<WrapPanel Orientation="Horizontal"
FocusManager.FocusedElement="{Binding ElementName=tbText}">
<CheckBox IsChecked="{Binding Path=Completed}" Margin="5" />
<Button Style="{StaticResource ResourceKey=DeleteButtonTemplate}"
Margin="5" Click="btnDeleteItem_Click" />
<TextBox Name="tbText"
Text="{Binding Path=Text}"
Width="200"
TextWrapping="Wrap"
AcceptsReturn="True"
Margin="5"
Focusable="True"/>
<DatePicker Text="{Binding Path=Date}" Margin="5"/>
</WrapPanel>
</Grid>
</DataTemplate>