Automatically select all text on focus in WinForms TextBox

Question

When a C# WinForms text box receives focus, I want to select all the text in the textbox.

To see what I mean, click in your web browser's address bar. See how all text was selected? I want to do that.

FASTEST GUN ALERT: please read the following before answering! Thanks guys. :-)

Calling .SelectAll() during the .Enter or .GotFocus events won't work because if the user clicked the textbox, the caret will be placed where he clicked, thus deselecting all text.

Also, calling .SelectAll() during the .Click event won't work because the user won't be able to select any text with the mouse; the .SelectAll() call will keep overwriting the user's text selection. )

Answer 1

Click event of textbox? Or even MouseCaptureChanged event works for me. - OK. doesn't work.

So you have to do 2 things:

private bool f = false;

private void textBox_MouseClick(object sender, MouseEventArgs e)
{ 
  if (this.f) { this.textBox.SelectAll(); }
  this.f = false;
}

private void textBox_Enter(object sender, EventArgs e)
{
  this.f = true;
  this.textBox.SelectAll();
}
private void textBox_MouseMove(object sender, MouseEventArgs e) // idea from the other answer
{
  this.f = false; 
}

Works for tabbing (through textBoxes to the one) as well - call SelectAll() in Enter just in case...

Answer 2

It's a bit kludgey, but in your click event, use SendKeys.Send( "{HOME}+{END}" );

Answer 3

'Inside the Enter event
TextBox1.SelectAll();

Ok, after trying it here is what you want:

• On the Enter event start a flag that states that you have been in the enter event
• On the Click event, if you set the flag, call .SelectAll() and reset the flag.
• On the MouseMove event, set the entered flag to false, which will allow you to click highlight without having to enter the textbox first.

This selected all the text on entry, but allowed me to highlight part of the text afterwards, or allow you to highlight on the first click.

By request:

    bool entered = false;
    private void textBox1_Enter(object sender, EventArgs e)
    {
        entered = true;
        textBox1.SelectAll();   //From Jakub's answer.
    }

    private void textBox1_Click(object sender, EventArgs e)
    {
        if (entered) textBox1.SelectAll();
        entered = false;
    }

    private void textBox1_MouseMove(object sender, MouseEventArgs e)
    {
        if (entered) entered = false;
    }

For me, the tabbing into the control selects all the text.

Answer 4

private bool _isSelected = false;
private void textBox_Validated(object sender, EventArgs e)
{
    _isSelected = false;
}

private void textBox_MouseClick(object sender, MouseEventArgs e)
{
    SelectAllText(textBox);
}

private void textBox_Enter(object sender, EventArgs e)
{
    SelectAllText(textBox);
}

private void SelectAllText(TextBox text)
{
    if (!_isSelected)
    {
        _isSelected = true;
        textBox.SelectAll();
    }
}

Answer 5

The below seems to work. The enter event handles the tabbing to the control and the MouseDown works when the control is clicked.

    private void textBox1_Enter(object sender, EventArgs e)
    {
        textBox1.SelectAll();
    }

    private void textBox1_MouseDown(object sender, MouseEventArgs e)
    {
        if (textBox1.Focused)
            textBox1.SelectAll();
    }

Answer 6

Interestingly, a ComboBox with DropDownStyle=Simple has pretty much exactly the behaviour you are looking for, I think.

(If you reduce the height of the control to not show the list - and then by a couple of pixels more - there's no effective difference between the ComboBox and the TextBox.)

Answer 7

Actually GotFocus is the right event (message really) that you are interested in, since no matter how you get to the control you’ll get this even eventually. The question is when do you call SelectAll().

Try this:

public partial class Form1 : Form
{
    public Form1()
    {
        InitializeComponent();
        this.textBox1.GotFocus += new EventHandler(textBox1_GotFocus);
    }

    private delegate void SelectAllDelegate();    
    private IAsyncResult _selectAllar = null; //So we can clean up afterwards.

    //Catch the input focus event
    void textBox1_GotFocus(object sender, EventArgs e)
    {
        //We could have gotten here many ways (including mouse click)
        //so there could be other messages queued up already that might change the selection.
        //Don't call SelectAll here, since it might get undone by things such as positioning the cursor.
        //Instead use BeginInvoke on the form to queue up a message
        //to select all the text after everything caused by the current event is processed.
        this._selectAllar = this.BeginInvoke(new SelectAllDelegate(this._SelectAll));
    }

    private void _SelectAll()
    {
        //Clean-up the BeginInvoke
        if (this._selectAllar != null)
        {
            this.EndInvoke(this._selectAllar);
        }
        //Now select everything.
        this.textBox1.SelectAll();
    }
}

Answer 8

Hi guys,

First of all, thanks for answers! 9 total answers. Thank you.

Bad news: all of the answers had some quirks or didn't work quite right (or at all). I've added a comment to each of your posts.

Good news: I've found a way to make it work. This solution is pretty straightforward and seems to work in all the scenarios (mousing down, selecting text, tabbing focus, etc.)

bool alreadyFocused;

...

textBox1.GotFocus += textBox1_GotFocus;
textBox1.MouseUp += textBox1_MouseUp;
textBox1.Leave += textBox1_Leave;

...

void textBox1_Leave(object sender, EventArgs e)
{
    alreadyFocused = false;
}


void textBox1_GotFocus(object sender, EventArgs e)
{
    // Select all text only if the mouse isn't down.
    // This makes tabbing to the textbox give focus.
    if (MouseButtons == MouseButtons.None)
    {
        this.textBox1.SelectAll();
        alreadyFocused = true;
    }
}

void textBox1_MouseUp(object sender, MouseEventArgs e)
{
    // Web browsers like Google Chrome select the text on mouse up.
    // They only do it if the textbox isn't already focused,
    // and if the user hasn't selected all text.
    if (!alreadyFocused && this.textBox1.SelectionLength == 0)
    {
        alreadyFocused = true;
        this.textBox1.SelectAll();
    }
}

As far as I can tell, this causes a textbox to behave exactly like a web browser's address bar.

Hopefully this helps the next guy who tries to solve this deceptively simple problem.

Thanks again, guys, for all your answers that helped lead me towards the correct path.

Answer 9

Why don't you simply use the MouseDown-Event of the text box? It works fine for me and doesn't need an additional boolean. Very clean and simple, eg.:

private void textbox_MouseDown(object sender, MouseEventArgs e) {
    if (textbox != null && !string.IsNullOrEmpty(textbox.Text))
    {
        textbox.SelectAll();
    } }

Answer 10

Have you tried the solution suggested on the MSDN Forum "Windows Forms General" which simply subclasses TextBox?

Answer 11

A one line answer that I use...you might be kicking yourself...

In the Enter Event:

txtFilter.BeginInvoke(new MethodInvoker( txtFilter.SelectAll));

Answer 12

I called SelectAll inside MouseUp event and it worked fine for me.

    private bool _tailTextBoxFirstClick = false;

    private void textBox1_MouseUp(object sender, MouseEventArgs e)
    {
        if(_textBoxFirstClick)           
            textBox1.SelectAll();

        _textBoxFirstClick = false;
    }  

    private void textBox1_Leave(object sender, EventArgs e)
    {
        _textBoxFirstClick = true;
        textBox1.Select(0, 0);
    }

Answer 13

Just derive a class from TextBox or MaskedTextBox:

public class SMaskedTextBox : MaskedTextBox
{
    protected override void OnGotFocus(EventArgs e)
    {
        base.OnGotFocus(e);
        this.SelectAll();
    }
}

And use it on your forms.

Answer 14

I created a new VB.Net Wpf project. I created one TextBox and used the following for the codebehind:

Class MainWindow 

Sub New()

    ' This call is required by the designer.
    InitializeComponent()

    ' Add any initialization after the InitializeComponent() call.
    AddHandler PreviewMouseLeftButtonDown, New MouseButtonEventHandler(AddressOf SelectivelyIgnoreMouseButton)
    AddHandler GotKeyboardFocus, New KeyboardFocusChangedEventHandler(AddressOf SelectAllText)
    AddHandler MouseDoubleClick, New MouseButtonEventHandler(AddressOf SelectAllText)
End Sub

Private Shared Sub SelectivelyIgnoreMouseButton(ByVal sender As Object, ByVal e As MouseButtonEventArgs)
    ' Find the TextBox
    Dim parent As DependencyObject = TryCast(e.OriginalSource, UIElement)
    While parent IsNot Nothing AndAlso Not (TypeOf parent Is TextBox)
        parent = VisualTreeHelper.GetParent(parent)
    End While

    If parent IsNot Nothing Then
        Dim textBox As Object = DirectCast(parent, TextBox)
        If Not textBox.IsKeyboardFocusWithin Then
            ' If the text box is not yet focussed, give it the focus and
            ' stop further processing of this click event.
            textBox.Focus()
            e.Handled = True
        End If
    End If
End Sub

Private Shared Sub SelectAllText(ByVal sender As Object, ByVal e As RoutedEventArgs)
    Dim textBox As Object = TryCast(e.OriginalSource, TextBox)
    If textBox IsNot Nothing Then
        textBox.SelectAll()
    End If
End Sub

End Class

Answer 15

Your solution is good, but fails in one specific case. If you give the TextBox focus by selecting a range of text instead of just clicking, the alreadyFocussed flag doesn't get set to true, so when you click in the TextBox a second time, all the text gets selected.

Here is my version of the solution. I've also put the code into a class which inherits TextBox, so the logic is nicely hidden away.

public class MyTextBox : System.Windows.Forms.TextBox
{
    private bool _focused;

    protected override void OnEnter(EventArgs e)
    {
        base.OnEnter(e);
        if (MouseButtons == MouseButtons.None)
        {
            SelectAll();
            _focused = true;
        }
    }

    protected override void OnLeave(EventArgs e)
    {
        base.OnLeave(e);
        _focused = false;
    }

    protected override void OnMouseUp(MouseEventArgs mevent)
    {
        base.OnMouseUp(mevent);
        if (!_focused)
        {
            if (SelectionLength == 0)
                SelectAll();
            _focused = true;
        }
    }
}