Regular Expression ask about it

Question

0.00/5 (No votes)

See more:

I have a textbox that is handled by a keypress. I want the textbox must accept only alphabet, numbers and allowing him to press the backspace.

how can i do it ?

but the backspace does not work

thanks for any fast reply

THANKS

Posted 12-May-13 5:21am

aymandesoky

Add a Solution

Comments

Andreas Gieriet 12-May-13 11:39am

What do you have coded so far?
What do you mean by "does not work"?
Your title does not make any sense to me...
Please rephrase your title, show your code that causes problems, and take the time to explain your problem in proper and full sentences.
Thanks
Andi

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2013-05-12T05:36:00

I would start by handling the TextChanged event for the TextBox - ignore the key events, as they will still allow unwanted data in via Paste (form keyboard or mouse).

In the TextChanged event, replace all unwanted characters with empty strings.

C#

private void MyTextBox_TextChanged(object sender, EventArgs e)
    {
    TextBox tb = sender as TextBox;
    if (tb != null)
        {
        string original = tb.Text;
        string revised = Regex.Replace(original, "[^\\w]", "");
        if (original != revised)
            {
            int cursor = tb.SelectionStart;
            tb.Text = revised;
            tb.SelectionStart = cursor;
            }
        }
    }