Question

This is what I have written:

if ((lstProperty[i].PropertyIdentifier as string).CompareTo('Name') == 0) 

Resharper put me an error (I am new with ReSharper… I am trying it) and it suggests me :

  if (((string) lstProperty[i].PropertyIdentifier).CompareTo('Name') == 0) 

Why is the second is NullException safe? For me both will crash if null value appear?

Answer 1

The ‘as’ operator will return null if the cast cannot be executed, while a C-style cast will throw an exception if it can’t cast.

I suggest breaking this out into multiple statements:

string propertyIdentifier = lstProperty[u].PropertyIdentifier as string; if(propertyIdentifier != null && propertyIdentifier.CompareTo('Name') == 0) {     ... your if statement ... } 

Resharper shouldn’t complain about this, and you also won’t get a NullReferenceException if the PropertyIdentifier is null or not a string.