Question

What’s the difference between the first and second definitions?

//1
private static string Mask
{
   get { return "some text"; }
}

//2 
private const string Mask  = "some text"; 

Which benefits has the first and the second approach?

Answer 1

As long as they are private they will probably be optimized to more or less the same code. The re is another story if they are public and used from other assemblies.

const variables will be substitued/inlined in other assemblies using the const expression. That means that you need to recompile every assembly using the const expression if you change the expression. On the other hand the property solution will give you a method call overhead each time used.