WPF TextBox.SelectAll () doesn't work

Question

Hi!

I have used the following template in my project:

<DataTemplate 
    x:Key="textBoxDataTemplate">
    <TextBox 
        Name="textBox"
        ToolTip="{Binding RelativeSource={RelativeSource Self}, Path=(Validation.Errors)[0].ErrorContent}"
        Tag="{Binding}"
        PreviewKeyDown="cellValueTextBoxKeyDown">
        <TextBox.Text>
            <MultiBinding
                Converter="{StaticResource intToStringMultiConverter}">
                <Binding 
                    Path="CellValue"
                    Mode="TwoWay">
                        <Binding.ValidationRules>
                            <y:MatrixCellValueRule 
                                MaxValue="200" />
                        </Binding.ValidationRules>
                </Binding>
                <Binding 
                    RelativeSource="{RelativeSource FindAncestor, AncestorType={x:Type y:MatrixGrid}}" 
                    Path="Tag"
                    Mode="OneWay" />
            </MultiBinding>
        </TextBox.Text>
    </TextBox>
</DataTemplate>

I used this template to create an editable matrix for the user. The user is able to navigate from cell to cell within the matrix and I would like to highlight the data in the selected textbox but it doesn't work. I called TextBox.Focus () and TextBox.SelectAll () to achieve the effect but nothing. The Focus () works but the text never gets highlighted.

Any help is welcome and appreciated.

Answer 1

Without the rest of your code it's difficult to say whether this will work for you, but I put together a small sample using your DataTemplate (minus the parts that refer to code that wasn't posted).

I was able to select all the text in the text boxes by adding a GotFocus event handler to the TextBox in the DataTemplate:

<TextBox 
    ...
    GotFocus="textBox_GotFocus"
    ...>
...
</TextBox>

And the code-behind:

 private void textBox_GotFocus(object sender, RoutedEventArgs e)
 {
  TextBox textBox = sender as TextBox;
  if (textBox != null)
  {
   textBox.SelectAll();
  }
 }

Let me know if you are attempting to select all under different circumstances (not when the box receives focus).

Answer 2

Okay, if anyone is interested, the solution to this problem of mine is to include the statement e.Handled = true; in the event handler method where the textBox.SelectAll () and textBox.Focus () are called. The problem was that I attached an event handler to the textbox's PreviewKeyDown event which handles a tunneling event and probabily the SelectAll () and Focus () calls are ignored without calling the e.Handled = true; statement.

Hope it'll help someone.