Question

Possible Duplicates:
Should I use public properties and private fields or public fields for data?
Difference between Automatic Properties and public field in C# 3.0

People seem to dogmatically insist on the use of public properties over fields but why is it so ultra-important in the case of simple properties?

How is

public int Foo { get; set; }

so incredibly different than

public int Foo;

?

Off the top of my head I can think of few practical differences between the two:

• Accessing the member using reflection (rare, and most decent reflective algorithms will account for the difference)
• The second entry allows you to use the field as a valid parameter for ref and out parameters, which would seem to be an advantage to using the field version
• Fields don’t work in Remoting (probably, I’ve never used remoting but I imagine they wouldn’t)?

Other than these fairly rare cases, changing Foo to be a computed property later results in 0 lines of code changed.

Answer 1

Using properties has a couple of distinct advantages:

• It allows for versioning if later you need extra logic. Adding logic to the getter or setter won’t break existing code.
• It allows data binding to work properly (most data binding frameworks don’t work with fields).

In addition, there are almost no disadvantages. Simple, automatic properties like this get inlined by the JIT compiler, so there is no reason not to use them.

Also, you mentioned:

Other than these fairly rare cases, changing Foo to be a computed property later results in 0 lines of code changed.

This doesn’t require your code to be changed, but it does force you to recompile all of your code. Changing from a field to a property is a breaking API change which will require any assembly which references your assembly to be recompiled. By making it an automatic property, you can just ship a new binary, and maintain API compatibility. This is the “versioning” advantage I mentioned above…