Is there a performance difference between properties vs. backing fields in read/write operations?

Question

When working within a class on its own fields and properties, I typically only use the property when it performs some function (like limiting a value or validating or whatever). Otherwise I prefer to read/write the backing field directly.

I somehow got it in my head that this would be a more generally performant way to do things, but it occurred to me that I don't really have any evidence to support this idea.

Aside from convention or taste, is there an actual performance factor between one and the other methods?

Answer 1

If the property is a straight get/set its compiled away - in other words, the compiler will turn either using the property or the field directly into the same thing - so no performance difference.

However, get/sets can incorporate whatever logic they want so can be expensive - however, guidelines often advise keeping them light.

Properties have a few benefits, even if they are just get/set covers:

• Data binding can only see properties, not fields.
• It keeps with the concept of encapsulation.
• You can enforce read only or write only semantics.
• You can apply attributes separately to the underlying field (useful in serialisation scenarios).

Just as an aside, although it is interesting to review the minute performance characteristics of these things - in production code applying this type of optimisation (well, in this case there isn't one) would likely come under the banner of premature optimisation.