String equality with null handling

Question

I will often use this code to compare a string:

if(!string.IsNullOrEmpty(str1) && str1.Equals(str2)){     //they are equal, do my thing } 

This handles the null case first etc.

Is there a cleaner way to do string comparison, perhaps with a single method call that will handle possible null values? I simply want to know that the strings are not equal if the testing value is null.

(I'm having dejavu that I may have asked this before, I apologize if so)

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Update: In my case, the str2 is a known good string to compare to, so I don't need to check it for null. str1 is the "unknown" string which may be null, so I want to say "str1 does not equal str2" in the cases where str1 is null...

Answer 1

Unlike Java, C# strings override the == operator:

if (str1 == str2) 

If you want a case-insensitive comparison:

if (string.Equals(str1, str2, StringComparison.OrdinalIgnoreCase)) 

Answer 2

If you do not want to treat two null strings as equal to each other, your code is optimal.

If, on the other hand, you want to treat null values as equal to each other, you can use

object.Equals(str1, str2) 

for a more "symmetric" approach that also handles null values.

This is not the only approach to a symmetric check of string equality that treats null strings as equal: you could also use string.Equals(str1, str2) or even str1 == str2, which redirects to string.Equals.