|Synopsis:||Test for empty strings using string length or String.IsNullOrEmpty|
When targeting .NET Framework 2.0 or newer, use the
IsNullOrEmpty method. Otherwise, use the
Length == comparison whenever possible.
Comparing strings using the
String.Length property or the
String.IsNullOrEmpty method is significantly faster than using
Equals. This is because
Equals executes significantly more MSIL instructions than either
IsNullOrEmpty or the number of instructions executed to retrieve the Length property value and compare it to zero./
You should be aware that
Length == 0 behave differently for null strings. If you try to get the value of the Length property on a null string, the common language runtime throws a
System.NullReferenceException. If you perform a comparison between a null string and the empty string, the common language runtime does not throw an exception; the comparison returns false. Testing for null does not significantly affect the relative performance of these two approaches.