Regex to check for blank space

Hi,

I have a textbox in my form I need a regex to check for blank space in that textbox value. How can I make it ?

#region Using Directives

using System;
using System.Text.RegularExpressions;

#endregion

public class Example
{
    static void Main()
    {
        string input = "hello";
        string regex = @"^[\S]*$";
        bool isMatch = false;
        isMatch = Regex.IsMatch(input, regex);
        Console.WriteLine(isMatch ? "{0}: Matched" : "{0}: Not Matched", input);

        input = "hello good";
        isMatch = Regex.IsMatch(input, regex);
        Console.WriteLine(isMatch ? "{0}: Matched" : "{0}: Not Matched", input);

        Console.ReadLine();
        //Output:

        //hello: Matched
        //hello good: Not Matched
    }
}