String - IsNotNullOrWhiteSpace

Indicates whether a specified string is not null, not empty, or not consists only of white-space characters.

Try it

public static void Main()
{
	string [] values = {"EntityFramework", "    ", "SQL", "", "Java", null};

	foreach(var str in values)
	{
		// C# Extension Method: String - IsNotNullOrWhiteSpace
    	if(str.IsNotNullOrWhiteSpace())
		{
			Console.WriteLine(str);
		}
	}
}

View Source
using System;

public static partial class Extensions
{
    /// <summary>
    ///     Indicates whether a specified string is not null, not empty, or not consists only of white-space characters.
    /// </summary>
    /// <param name="value">The string to test.</param>
    /// <returns>true if the  parameter is null or , or if  consists exclusively of white-space characters.</returns>
    public static Boolean IsNotNullOrWhiteSpace(this string value)
    {
        return !String.IsNullOrWhiteSpace(value);
    }
}