Methods inside enum in C#

问题:

In Java, it's possible to have methods inside an enum.

Is there such possibility in C# or is it just a string collection and that's it?

I tried to override ToString() but it does not compile. Does someone have a simple code sample?

回答1:

You can write extension methods for enum types:

enum Stuff
{
    Thing1,
    Thing2
}

static class StuffMethods
{

    public static String GetString(this Stuff s1)
    {
        switch (s1)
        {
            case Stuff.Thing1:
                return "Yeah!";
            case Stuff.Thing2:
                return "Okay!";
            default:
                return "What?!";
        }
    }
}

class Program
{


    static void Main(string[] args)
    {
        Stuff thing = Stuff.Thing1;
        String str = thing.GetString();
    }
}

回答2:

You can write an extension method for your enum:

How to: Create a New Method for an Enumeration (C# Programming Guide)

回答3:

Another option is to use the Enumeration Class created by Jimmy Bogard.

Basically, you must create a class that inherits from his Enumeration. Example:

public class EmployeeType : Enumeration
{
    public static readonly EmployeeType Manager 
        = new EmployeeType(0, "Manager");
    public static readonly EmployeeType Servant 
        = new EmployeeType(1, "Servant");
    public static readonly EmployeeType Assistant
        = new EmployeeType(2, "Assistant to the Regional Manager");

    private EmployeeType() { }
    private EmployeeType(int value, string displayName) : base(value, displayName) { }

    // Your method...
    public override string ToString()
    {
        return $"{value} - {displayName}!";
    }
}

Then you can use it like an enum, with the possibility to put methods inside it (among another things):

EmployeeType.Manager.ToString();
//0 - Manager
EmployeeType.Servant.ToString();
//1 - Servant
EmployeeType.Assistant.ToString();
//2 - Assistant to the Regional Manager

You can download it with NuGet.

回答4:

Nope. You can create a class, then add a bunch of properties to the class to somewhat emulate an enum, but thats not really the same thing.

class MyClass
{
    public string MyString1 { get{ return "one";} }
    public string MyString2 { get{ return "two";} }
    public string MyString3 { get{ return "three";} }

    public void MyMethod()
    {
        // do something.
    }
}

A better pattern would be to put your methods in a class separate from your emum.

回答5:

C# Does not allow use of methods in enumerators as it is not a class based principle, but rather an 2 dimensional array with a string and value.

Use of classes is highly discouraged by Microsoft in this case, use (data)struct(ures) instead; The STRUCT is intended as a light class for data and its handlers and can handle functions just fine. C# and its compiler don't have the tracking and efficiency capabilities as one knows from JAVA, where the more times a certain class / method is used the faster it runs and its use becomes 'anticipated'. C# simply doesn't have that, so to differentiate, use STRUCT instead of CLASS.