Regular Expression for AlphaNumeric Characters only

Regular Expression for AlphaNumeric Characters only :

^[0-9a-zA-Z\s]+$

It only allows 0-9,a-z, A-Z, $

Creating Regular Expression for Numeric Values and using it on a TextBox control in C#

//Creating regular expression for numeric values
Regex rxNum = new Regex(@"^[0-9\s]+$");

//using regular expression on  a TextBox Control in C#
if (!rxNum.IsMatch(textbox1.Text))
          Response.write("Textbox1 has Numeric value");