Set the focus on a textbox in xaml wpf

Question

Despite some posts on this forum and others i cannot find something that tells me how to set the focus on a TextBox.

I have a userControl with many labels and textBoxes. When the form is loaded I want the a particular textBox to have the focus.

I have set the tabIndex but that didn't seem to work.

Any suggestions?

Answer 1

You can use the FocusManager.FocusedElement attached property for this purpose. Here's a piece of code that set the focus to TxtB by default.

<StackPanel Orientation="Vertical" FocusManager.FocusedElement="{Binding ElementName=TxtB}">
    <TextBox x:Name="TxtA" Text="A" />
    <TextBox x:Name="TxtB" Text="B" />
</StackPanel>

You can also use TxtB.Focus() in your code-behind if you don't want to do this in XAML.

Answer 2

You can apply this property directly on the TextBox :

<TextBox Text="{Binding MyText}" FocusManager.FocusedElement="{Binding RelativeSource={RelativeSource Self}}"/>

Answer 3

I am new to using WPF and reading through the above examples I had a similar experience trying set the focus to a textbox using the xaml code examples given, i.e. all the examples above didn't work.

What I found was I had to place the FocusManager.FocusElement in the page element. I assume this would probably work as well if you used a Window as the parent element. Anyway, here is the code that worked for me.

 <Page x:Class="NameOfYourClass"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
  xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
  mc:Ignorable="d"
  Title="Title" 
  Height="720"
  Width="915"
  Background="white"
  Loaded="pgLoaded"
  FocusManager.FocusedElement="{Binding ElementName=NameOfYourTextBox}">

  <!-- Create child elements here. -->

  </Page>

Answer 4

I have a TextBox inside a Grid inside a DataTemplate which I want to have keyboard focus when it becomes visible. I also found that

<DataTemplate x:Key="DistanceView" DataType="{x:Type vm:ROI}">
    <Grid FocusManager.FocusedElement="{Binding ElementName=tbDistance}">
        <TextBox x:Name="tbDistance" Grid.Column="1" Grid.Row="1" VerticalAlignment="Bottom"/>
    </Grid>
</DataTemplate>

did not work for me.

However when I call Focus() in the parent ContentControl

private void ContentControl_IsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
{
    if ((sender as ContentControl).IsVisible)
    {
        (sender as ContentControl).Focus();
    }
}

it starts to work and the caret is visible in the TextBox. I think the FocusScope has to be given focus for the FocusManager.FocusedElement property to have any effect.

Jerry

Answer 5

bind the element you want to point the focus in as

FocusManager.FocusedElement= "{Binding ElementName= Comobox1}"

in grid or groupbox etc

Answer 6

FocusManager was not in intellisense and this confused me a bit. I just typed the entire attribute and it worked.

FocusManager.FocusedElement="{Binding ElementName=MyTextBox}"

---

Microsoft Visual Studio Enterprise 2015 version 14.0.23107.0/C#/WPF

Answer 7

For completeness, there is also a way to handle this from code behind (e.g. in the case of controls that, for whatever reason, are created dynamically and don't exist in XAML). Attach a handler to the window's Loaded event and then use the ".Focus()" method of the control you want. Bare-bones example below.

public class MyWindow
{
    private VisualCollection controls;
    private TextBox textBox;

    // constructor
    public MyWindow()
    {
        controls = new VisualCollection(this);
        textBox = new TextBox();
        controls.Add(textBox);

        Loaded += window_Loaded;
    }

    private void window_Loaded(object sender, RoutedEventArgs e)
    {
        textBox.Focus();
    }
}

Answer 8

From experimenting around, the xaml solution

FocusManager.FocusedElement="{Binding ElementName=yourElement}"

seems to work best when you place it in the highest element in the window hierarchy (usually Window, or the Grid you place everything else in)

Answer 9

Usage: local:FocusManager.FocusOnLoad="True"

    public class FocusManager
    {
        public static readonly DependencyProperty FocusOnLoad = DependencyProperty.RegisterAttached(
            "FocusOnLoad",
            typeof(bool),
            typeof(FocusManager),
            new UIPropertyMetadata(false, new PropertyChangedCallback(OnValueChanged))
            );

        private static void OnValueChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
        {
            if (!(sender is Control control))
                return;

            if ((bool) e.NewValue == false)
                return;

            control.Loaded += (s, e) => control.Focus();
        }

        public static bool GetFocusOnLoad(DependencyObject d) => (bool) d.GetValue(FocusOnLoad);

        public static void SetFocusOnLoad(DependencyObject d, bool value) => d.SetValue(FocusOnLoad, value);
    }