string.IsNullOrEmpty(string) vs. string.IsNullOrWhiteSpace(string)

Question

Is use of string.IsNullOrEmpty(string) when checking a string considered as bad practice when there is string.IsNullOrWhiteSpace(string) in .NET 4.

Answer 1

The differences in practice :

string testString = "";
Console.WriteLine(string.Format("IsNullOrEmpty : {0}", string.IsNullOrEmpty(testString)));
Console.WriteLine(string.Format("IsNullOrWhiteSpace : {0}", string.IsNullOrWhiteSpace(testString)));
Console.ReadKey();

Result :
IsNullOrEmpty : True
IsNullOrWhiteSpace : True

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string testString = " MDS   ";

IsNullOrEmpty : False
IsNullOrWhiteSpace : False

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string testString = "   ";

IsNullOrEmpty : False
IsNullOrWhiteSpace : True

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string testString = string.Empty;

IsNullOrEmpty : True
IsNullOrWhiteSpace : True

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string testString = null;

IsNullOrEmpty : True
IsNullOrWhiteSpace : True