.NET: String.IsNullOrWhiteSpace Method

http://msdn.microsoft.com/en-us/library/system.string.isnullorwhitespace%28VS.100%29.aspx

Indicates whether a specified string is Nothing, empty, or consists only of white-space characters.

Handy little static method added in .NET 4.0, used in this way:

using System;

public class Example
{
   public static void Main()
   {
      string[] values = { null, String.Empty, "ABCDE", 
                          new String(' ', 20), "  \t   ", 
                          new String('\u2000', 10) };
      foreach (string value in values)
         Console.WriteLine(String.IsNullOrWhiteSpace(value));
   }
}
// The example displays the following output:
//       True
//       True
//       False
//       True
//       True
//       True