Accept only certain strings for a method in C#

Question

I've created a method in C# as you can see below

public static IEnumerable<User> QueryTheAD(string filter, string identifier) {
  if ( filter == "ANiceString" ) {
    // sexy code here
  }
}

which works well. However VS rightly shows that not all code path returns a value.

So is it therefore possible for me to specify that filter can only be one of these:

• "Tutor"
• "Year"
• "SecondName"

Answer 1

Maybe you should use an enum instead of string? :)

enum filterEnum
{
   Tutor,
   Year,
   SecondName
}

public static IEnumerable<User> QueryTheAD(filterEnum filter, string identifier) 

Enjoy ;)