[c#] How can I check a C# variable is an empty string "" or null?

I am looking for the simplest way to do a check. I have a variable that can be equal to "" or null. Is there just one function that can check if it's not "" or null?

if (string.IsNullOrEmpty(myString)) 
{
  . . .
  . . .
}

Cheap trick:

Convert.ToString((object)stringVar) == “”

This works because Convert.ToString(object) returns an empty string if object is null. Convert.ToString(string) returns null if string is null.

(Or, if you're using .NET 2.0 you could always using String.IsNullOrEmpty.)

Since .NET 2.0 you can use:

// Indicates whether the specified string is null or an Empty string.
string.IsNullOrEmpty(string value);

Additionally, since .NET 4.0 there's a new method that goes a bit farther:

// Indicates whether a specified string is null, empty, or consists only of white-space characters.
string.IsNullOrWhiteSpace(string value);

string.IsNullOrEmpty is what you want.

if the variable is a string

bool result = string.IsNullOrEmpty(variableToTest);

if you only have an object which may or may not contain a string then

bool result = string.IsNullOrEmpty(variableToTest as string);