Foreach on enum types in template

问题

enum MyEnum
{
type1,
type2,
type3
}

public void MyMethod<T>()
{
...
}

How to make forach on enum to fire MyMethod<T> on every enum?

I try something with

foreach (MyEnum type in Enum.GetValues(typeof(MyEnum)))
{...}

But still don't know how to use this type inside foreach with MyMethod<T> as T

回答1:

Is this what you are trying to do?

class Program
{
    static void Main(string[] args)
    {
        EnumForEach<MyEnum>(MyMethod);
    }

    public static void EnumForEach<T>(Action<T> action)
    {
        if(!typeof(T).IsEnum)
            throw new ArgumentException("Generic argument type must be an Enum.");

        foreach (T value in Enum.GetValues(typeof(T)))
            action(value);
    }

    public static void MyMethod<T>(T enumValue)
    {
        Console.WriteLine(enumValue);
    }
}

Writes to the console:

type1
type2
type3

回答2:

this code snippet demonstrates how to show all enum values as a chained string in a message box. In the same way you can make the method perform what you want on the enums.

namespace Whatever
{
    enum myEnum
    {
        type1,type2,type3
    }

    public class myClass<T>
    {
        public void MyMethod<T>()
        {
            string s = string.Empty;
            foreach (myEnum t in Enum.GetValues(typeof(T)))
            {
                s += t.ToString();
            }
            MessageBox.Show(s);
        }
    }

    public void SomeMethod()
    {
        Test<myEnum> instance = new Test<myEnum>();
        instance.MyMethod<myEnum>(); //wil spam the messagebox with all enums inside
    }
}

回答3:

You can do

private List<T> MyMethod<T>()
{
    List<T> lst = new List<T>;

    foreach (T type in Enum.GetValues(source.GetType()))
    {
        lst.Add(type); 
    }

   return lst;
}

and call it as

List<MyEnum> lst = MyMethod<ResearchEnum>();

来源：https://stackoverflow.com/questions/11361635/foreach-on-enum-types-in-template