textbox validation

Question

how to restrict a textbox from accepting special chracters

Hemant Srivastava · Answer

If its a desktop application, then use this code to avoid special characters private void txtBx_CountWords_KeyPress(object sender, KeyPressEventArgs e) { if (Char.IsLetterOrDigit(e.KeyChar)) // Allowing only any letter OR Digit { e.Handled = false; } else { e.Handled = true; } }

Hemant Srivastava · Answer

Generally one should allow backspace character too alongwith alphanumeric characters so that user could remove any wrong character if he entered by mistake. In order to do that, you need to add one more conition in the if block as private void txtBx_KeyPress(object sender, KeyPressEventArgs e) { if (Char.IsLetterOrDigit(e.KeyChar) // Allowing only any letter OR Digit ||e.KeyChar == '\b') // Allowing BackSpace character { e.Handled = false; } else { e.Handled = true; } } Let me know if it doesn't solve your problem.

ta mu · Answer

this is a desktop aplication i got error regex type or name space could not found

Jaganathan Bantheswaran · Answer

Hi, You can do it in server/client side, Server Side: private void textBox1_KeyPress(object sender, KeyPressEventArgs e) { var regex = new Regex(@"[^a-zA-Z0-9\s]"); if (regex.IsMatch(e.KeyChar.ToString())) { e.Handled = true; } } Client Side: Alphanumeric value: * Special Characters not allowed var specialKeys = new Array(); specialKeys.push(8); //Backspace specialKeys.push(9); //Tab specialKeys.push(46); //Delete specialKeys.push(36); //Home specialKeys.push(35); //End specialKeys.push(37); //Left specialKeys.push(39); //Right function IsAlphaNumeric(e) { var keyCode = e.keyCode == 0 ? e.charCode : e.keyCode; var ret = ((keyCode >= 48 && keyCode = 65 && keyCode = 97 && keyCode document.getElementById("error").style.display = ret ? "none" : "inline"; return ret; }