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

Use an enum or throw an ArgumentException if an invalid string was passed.

While enums only map to numbers, you could always have a mapping from the enum values to the strings in case you need string names for some reason.