using System;

using System.Linq;

using static C;

​

Console.WriteLine(C.IntToEnum<E>(0));

Console.WriteLine(C.IntToEnum<E>(100));

​

public enum E { A = 0, B = 100 }

​

public static class C {

    public static TEnum IntToEnum<TEnum>(int i) where TEnum : Enum

    {

        Array array = Enum.GetValues(typeof(TEnum));

        int[] intValues = (int[])array;

        TEnum[] enumValues = (TEnum[])array;

        var b = intValues.Zip(enumValues);

        //Consider saving the dictionary to avoid recreating each time

        var c = b.ToDictionary<(int n, TEnum e), int, TEnum>(p => p.n, p => p.e);

        return c[i];//KeyNotFoundException possible here

    }

}