Question

What is the main difference between the following two declarations?

public string Name
{
  get { return "Settings"; }
}

and

public const string Name = "Settings";

Aren’t both prevented from being changed?

Answer 1

The first is a property which only provides a get accessor. This is specified per instance.

The second is a compile time constant. At compile time, it will be replaced with "Settings", so it is not really a member of the type at all.

The const declaration does have the advantage of eliminating a method call (as it’s just a compile time constant value), however, the property call will likely get eliminated by the JIT at runtime.

The property declaration has the advantage of allowing you to change how this works later, without breaking compatibility – even binary compatibility. In order to see a change in the const value, a full recompilation of everything that uses it would be required, even if it’s in separate assemblies.

Basically, a public const is probably a good idea, but only if this is a value that will never change – not a value that will never change during the runtime of the program, but that will never change anywhere, at any time. Int32.MaxValue is a good example – this has a specific meaning that is based on the Int32 type itself – there’s no way that this would ever change. As such, it makes sense as a public const. In your case, "Settings" may be something you’d want to change eventually – if that’s the case, then encapsulating it in a property makes sense.