How to force textbox to take only numbers in WPF?

Question

I want user to enter only numeric values in TextBox.

I got this code:

private void txtType1_KeyPress(object sender, KeyPressEventArgs e)
{
     int isNumber = 0;
     e.Handled = !int.TryParse(e.KeyChar.ToString(), out isNumber);
}

But I am not getting textbox_KeyPress event and e.KeyChar while using WPF.

Whats the solution in WPF?

Edit:

I made a Solution!

private void txtName_PreviewTextInput(object sender, TextCompositionEventArgs e)
{
    CheckIsNumeric(e);
}

private void CheckIsNumeric(TextCompositionEventArgs e)
{
    int result;

    if(!(int.TryParse(e.Text, out result) || e.Text == "."))
    {
        e.Handled = true;
    }
}

[View here](http://stackoverflow.com/questions/1268552/how-do-i-get-a-textbox-to-only-accept-numeric-input-in-wpf) You can find here a good overview of answers for it. — Pinotek, Oct 17 '16 at 10:17

score 18 · Answer 1 · answered Jun 23 '12 at 06:52

18

protected override void OnPreviewTextInput(TextCompositionEventArgs e)
    {
        char c = Convert.ToChar(e.Text);
        if (Char.IsNumber(c))
            e.Handled = false;
        else
            e.Handled = true;

        base.OnPreviewTextInput(e);
    }

answered Jun 23 '12 at 06:52

Niki Nikpour

211
2
4

4

Good answer! Although, I would replace all but the last line of your method body with e.Handled = !Char.IsNumber(Convert.ToChar(e.Text)); – Anna Lam Jul 06 '12 at 05:30
10

`PreviewTextInput()` will not catch the 'space' key press. Adding `if (e.Key == Key.Space) e.Handled = true;` in the `PreviewKeyDown()` would solve that problem. – Igor Oct 13 '13 at 16:29
2

This answer doesn't solve problem of user pasting a value into the textbox. The pasted value could contain letters. – dcp Feb 02 '16 at 19:19

score 8 · Answer 2 · answered May 11 '11 at 16:11

8

You can use a validation rule... http://www.codeproject.com/KB/WPF/wpfvalidation.aspx

Or make your own Maskable textbox http://rubenhak.com/?p=8

answered May 11 '11 at 16:11

Phil Murray

6,396
9
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score 1 · Answer 3 · answered Jul 12 '13 at 04:26

bit enhanced version of Hasib Uz Zaman

     private void txtExpecedProfit_PreviewTextInput_1(object sender, TextCompositionEventArgs e)
    {
        CheckIsNumeric((TextBox)sender,e);
    }

    private void CheckIsNumeric(TextBox sender,TextCompositionEventArgs e)
    {
        decimal result;
        bool dot = sender.Text.IndexOf(".") < 0 && e.Text.Equals(".") && sender.Text.Length>0;
        if (!(Decimal.TryParse(e.Text, out result ) || dot )  )
        {
            e.Handled = true;
        }
    }

this will check for duplication .(decimal mark) and will not allow just only .(decimal mark)

score 1 · Answer 4 · edited Apr 06 '17 at 19:30

1

//Call this code on KeyDown Event
if((e.Key >= Key.NumPad0 && e.Key <= Key.NumPad9) || (e.Key == Key.Back))
{ e.Handled = false; }
else if((e.Key >= Key.D0 && e.Key <= Key.D9))
{ e.Handled = false; }
else
{ e.Handled = true; }

edited Apr 06 '17 at 19:30

Uwe Keim

39,551
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answered Apr 06 '17 at 19:09

suyog patil

11
3

score 1 · Answer 5 · answered May 11 '11 at 16:26

You can bind your textbox with a dependency property and inside dependency property's validation method you can check if int.tryparse returns true then fine otherwise you can go for default or you can reset value.

Or you can use WPF ValidationRules to find out when the value is changed. Once changed you can apply logic for inout validaiton.

Or you can use IDataError Info for validation.

score 0 · Answer 6 · answered Mar 27 '13 at 07:42

0

In WPF the keycode values are different from the normal winforms e.keychar values,

In the PreviewKeyDown event of the textbox, add this code:

if ((e.key < 34) | (e.key > 43)) {
if ((e.key < 74) | (e.key > 83)) {
    if ((e.key == 2)) {
        return;
        }
    e.handled = true;
    }
}

This will allow the User to only enter Numbers in the Numpad0 - Numpad9 section and the D0 - D9 and also the key.Back

Hope this Helps, cheers!

answered Mar 27 '13 at 07:42

George

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6

not working in conjunction to Shift. You can insert special characters – Dragos Stoica Mar 18 '16 at 12:46

score 0 · Answer 7 · edited Apr 09 '17 at 14:45

0

private void shomaretextBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
{
  // xaml.cs code
  if (!char.IsDigit(e.Text, e.Text.Length - 1))
    e.Handled = true;
}

In xaml

<TextBox x:Name="shomaretextBox" 
         HorizontalAlignment="Left" 
         Height="28" 
         Margin="125,10,0,0" 
         TextWrapping="Wrap" 
         VerticalAlignment="Top" 
         Width="151" 
         Grid.Column="1"        
         TextCompositionManager.PreviewTextInput="shomaretextBox_PreviewTextInput" />

edited Apr 09 '17 at 14:45

Jeroen Heier

3,520
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answered Apr 09 '17 at 08:26

amin zare

23
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Better if you could add some explanation, dome details, not code only. The idea is that other users could also benefit from your answer as well (in the future), not only the OP. Just a thought :) – סטנלי גרונן Apr 09 '17 at 08:52

score -1 · Answer 8 · answered May 11 '11 at 16:14

-1

I believe what you're looking for is the PreviewTextInput event.

answered May 11 '11 at 16:14

Bubblewrap

7,266
1
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33

How to force textbox to take only numbers in WPF?

8 Answers8