need to create a summary of a large switch statement in C#

Question

Alright, i dont know how to explain it well.. but i have a switch statement,

string mystring = "hello";
switch(mystring)
{
case "hello":
break;
case "goodbye":
break;
case "example":
break;
}

of course this is an example, and in the real situation, there will be different things happening for each case. ok, hope you get the point, now, doing this manually is impossible, because of the sheer number of different case's. i need to respectively create a list, of all the cases, so for instance.. for the above switch statement, i would need

string[] list = { "hello", "goodbye", "example" };

maybe could be done with a foreach some how i dont know, any help would be greatly appreciated.

also, any working codes provided would be awesome!

edit: people are asking for more detail, so here is how it works. the user of the program, inputs a series of strings. based on the string(s) they entered, it will do a few if's and else if's and throw back the new strings basically. i need to be able to be able to create a list, through the program, of all the options available to use. and i cant just make a list and hard code it in, because im always adding more case's to the statement, and i cant be going back and keeping a list up to date.

Answer 1

It depends on how clever you want to get... You could create a custom attribute that attaches to a method with the string that method should handle. Then, instead of a switch statement, you would just find the attribute with your desired value and execute it.

using System;
using System.Reflection;

namespace ConsoleApplication1 {
    [AttributeUsage(AttributeTargets.Method)]
    internal class ProvidesAttribute : Attribute {
        private String[] _strings;
        public ProvidesAttribute(params String[] strings) {
            _strings = strings;
        }
        public bool Contains(String str) {
            foreach (String test in _strings) {
                if (test.Equals(str)) {
                    return true;
                }
            }
            return false;
        }
    }

    internal class Program {
        [Provides("hello", "goodbye")]
        public void HandleSomeStuff(String str) {
            Console.WriteLine("some stuff: {0}", str);
        }

        [Provides("this")]
        public void HandleMoreStuff(String str) {
            Console.WriteLine("more stuff: {0}", str);
        }

        public void HandleString(String str) {
            // we could loop through each Type in the assembly here instead of just looking at the
            // methods of Program; this would allow us to push our "providers" out to other classes
            MethodInfo[] methods = typeof(Program).GetMethods();
            foreach (MethodInfo method in methods) {
                Attribute attr = Attribute.GetCustomAttribute(method, typeof(ProvidesAttribute));
                ProvidesAttribute prov = attr as ProvidesAttribute;
                if ((prov != null) && (prov.Contains(str))) {
                    method.Invoke(this, new Object[] { str } );
                    break;  // removing this enables multiple "providers"
                }
            }
        }

        internal static void Main(String[] args) {
            Program prog = new Program();
            foreach (String str in args) {
                prog.HandleString(str);
            }
        }
    }
}

Once you have the framework, you wouldn't need to alter the HandleString() code, just add the methods you want to take care of and set the Provides attribute on them. If you wanted to extend the idea a little further, you could create multiple classes to handle a wide variety of strings, then loop through each type in your assembly looking for the Provides attribute.

EDIT this has the added benefit that you can define multiple methods that act on the same string (by removing the break in the loop logic).