Auto highlight text in a textbox control

Question

How do you auto highlight text in a textbox control when the control gains focus.

Answer 1

On events "Enter" (for example: press Tab key) or "First Click" all text will be selected. dotNET 4.0

public static class TbHelper
{
    // Method for use
    public static void SelectAllTextOnEnter(TextBox Tb)
    {
        Tb.Enter += new EventHandler(Tb_Enter);
        Tb.Click += new EventHandler(Tb_Click);
    }

    private static TextBox LastTb;

    private static void Tb_Enter(object sender, EventArgs e)
    {
        var Tb = (TextBox)sender;
        Tb.SelectAll();
        LastTb = Tb;
    }

    private static void Tb_Click(object sender, EventArgs e)
    {
        var Tb = (TextBox)sender;
        if (LastTb == Tb)
        {
            Tb.SelectAll();
            LastTb = null;
        }
    }
}

Answer 2

 textBoxX1.Focus();
 this.ActiveControl = textBoxX1;
 textBoxX1.SelectAll();

Answer 3

Here's the code I've been using. It requires adding the attached property to each textbox you wish to auto select. Seeing as I don't want every textbox in my application to do this, this was the best solution to me.

public class AutoSelectAll
{
    public static bool GetIsEnabled(DependencyObject obj) 
    { 
        return (bool)obj.GetValue(IsEnabledProperty); 
    } 
    public static void SetIsEnabled(DependencyObject obj, bool value) 
    { 
        obj.SetValue(IsEnabledProperty, value);
    }

    static void ue_Loaded(object sender, RoutedEventArgs e)
    {
        var ue = sender as FrameworkElement;
        if (ue == null)
            return;
        ue.GotFocus += ue_GotFocus;
        ue.GotMouseCapture += ue_GotMouseCapture;
    }

    private static void ue_Unloaded(object sender, RoutedEventArgs e)
    {
        var ue = sender as FrameworkElement;
        if (ue == null)
            return;
        //ue.Unloaded -= ue_Unloaded;
        ue.GotFocus -= ue_GotFocus;
        ue.GotMouseCapture -= ue_GotMouseCapture;
    }

    static void ue_GotFocus(object sender, RoutedEventArgs e)
    {
        if (sender is TextBox)
        {
            (sender as TextBox).SelectAll();
        }
        e.Handled = true;
    }

    static void ue_GotMouseCapture(object sender, MouseEventArgs e)
    {
        if (sender is TextBox)
        {
            (sender as TextBox).SelectAll();
        }
        e.Handled = true;
    }

    public static readonly DependencyProperty IsEnabledProperty = DependencyProperty.RegisterAttached("IsEnabled", typeof(bool),
        typeof(AutoSelectAll), new UIPropertyMetadata(false, IsEnabledChanged));

    static void IsEnabledChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
    {
        var ue = d as FrameworkElement;
        if (ue == null)
            return;
        if ((bool)e.NewValue)
        {
            ue.Unloaded += ue_Unloaded;
            ue.Loaded += ue_Loaded;
        }
    }
} 

The main change I made here was adding a loaded event to many of the examples I've seen. This allows the code to continue working after it's unloaded (ie. a tab is changed). Also I included code to make sure the text gets selected if you click on the textbox with the mouse, and not just keyboard focus it. Note: If you actually click on the text in the textbox, the cursor is inserted between the letters as it should.

You can use this by including the following tag in your xaml.

<TextBox  
    Text="{Binding Property}"
    Library:AutoSelectAll.IsEnabled="True" />

Answer 4

I think the easiest way is using TextBox.SelectAll like in an Enter event:

private void TextBox_Enter(object sender, EventArgs e)
{
    ((TextBox)sender).SelectAll();
}

Answer 5

I don't know why nobody mentioned that but you can also do this, it works for me

textbox.Select(0, textbox.Text.Length)

Answer 6

If you need to do this for a large number of textboxes (in Silverlight or WPF), then you can use the technique used in the blog post: http://dnchannel.blogspot.com/2010/01/silverlight-3-auto-select-text-in.html. It uses Attached Properties and Routed Events.