Validate numeric textbox using int.tryparse visual C#.NET

The alternative posted by Daaron does not work for several cases. E.g. Sign is included (+ or -), text contains whitespace prefix or suffix, etc. You could fix the first two limitations with a more detailed regex like "(^\s*(-|\+)?\d+\s*$)" but you could still end up with a value that won't fit...

You could always run the TryParse on the keyDown event so as to validate as the data gets entered. It saves the user an additional UI interaction. private void textBox1_KeyDown(object sender, KeyEventArgs e) { int i; string s = string.Empty; ...

You could do the same thing with a regular expression:if (Regex.Replace(textBox1.Text, @"\D", "") == textBox1.Text){textBox2.Text = ("tryparse method succeed");} else { textBox2.Text=("value entered is not numeric"); }

using Microsoft.VisualBasic;// Codebool result = Information.IsNumeric("123");

See my article at Numeric Validator for Web Text Controls[^]

Here is some old Delphi code that you could use to get more out of floating points strings before using TryParse().It will sanitize numbers like .25E4 or 10.E2 or -.24, all illegal in Double.TryParse.The code will also replace all non-floating point characters by a decimal separator (the...