how to check whether a number or letter has been entered in a textbox on KeyUp Event

Question

On KeyPress or KeyUp event, how can I do something like this:

if (String.IsOnlyANumber(textBox.Text))
{ 
    do my things
}
else if(String.IsLettersAndEverythingElse(textBox.Text))
{
    do my other things
}

Duplicate of: [how to check if the character is an integer](https://stackoverflow.com/questions/12866214/how-to-check-if-the-character-is-an-integer), [How do I make a textbox that only accepts numbers?](https://stackoverflow.com/q/463299/8967612) — 41686d6564 stands w. Palestine, Oct 29 '20 at 07:27
@41686d6564 why did you change the link? the last one was better — James Jefferson Johnson, Oct 29 '20 at 08:03
I didn't change the link. There are two links in my comment. The first post tells you how to check if a char is a digit and the second one tells you how to _get_ the char (in case you didn't know how) in the `KeyPress` event. — 41686d6564 stands w. Palestine, Oct 29 '20 at 08:06
@41686d6564 sorry, my bad. Didn't saw it :D struggling hard in the mornings — James Jefferson Johnson, Oct 29 '20 at 08:09

score 0 · Answer 1 · answered Oct 29 '20 at 07:26

0

private void your_textBox_KeyPress(object sender, KeyPressEventArgs e)
{
    if (char.IsDigit(e.KeyChar)) 
    {
        // is a number
    }
    else 
    {
        // is anything else
    }
}

answered Oct 29 '20 at 07:26

juergen d

201,996
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score -1 · Answer 2 · answered Oct 29 '20 at 07:32

-1

try this,

textBox1.Text = string.Concat(textBox1.Text.Where(char.IsLetterOrDigit));

in your KeyPress or KeyUp event.

answered Oct 29 '20 at 07:32

Swapnil Hendre

1
1

how to check whether a number or letter has been entered in a textbox on KeyUp Event

2 Answers2