Get int value from enum in C#

Question

I have a class called Questions (plural). In this class there is an enum called Question (singular) which looks like this.

public e         


        

Answer 1

Maybe I missed it, but has anyone tried a simple generic extension method?

This works great for me. You can avoid the type cast in your API this way but ultimately it results in a change type operation. This is a good case for programming Roslyn to have the compiler make a GetValue<T> method for you.

    public static void Main()
    {
        int test = MyCSharpWrapperMethod(TestEnum.Test1);

        Debug.Assert(test == 1);
    }

    public static int MyCSharpWrapperMethod(TestEnum customFlag)
    {
        return MyCPlusPlusMethod(customFlag.GetValue<int>());
    }

    public static int MyCPlusPlusMethod(int customFlag)
    {
        // Pretend you made a PInvoke or COM+ call to C++ method that require an integer
        return customFlag;
    }

    public enum TestEnum
    {
        Test1 = 1,
        Test2 = 2,
        Test3 = 3
    }
}

public static class EnumExtensions
{
    public static T GetValue<T>(this Enum enumeration)
    {
        T result = default(T);

        try
        {
            result = (T)Convert.ChangeType(enumeration, typeof(T));
        }
        catch (Exception ex)
        {
            Debug.Assert(false);
            Debug.WriteLine(ex);
        }

        return result;
    }
}

Answer 2

Try this one instead of convert enum to int:

public static class ReturnType
{
    public static readonly int Success = 1;
    public static readonly int Duplicate = 2;
    public static readonly int Error = -1;        
}

Answer 3

You should have used Type Casting as we can use in any other language.

If your enum is like this-

public enum Question
{
    Role = 2,
    ProjectFunding = 3,
    TotalEmployee = 4,
    NumberOfServers = 5,
    TopBusinessConcern = 6
}

And you need to cast to an int, then do this-

Question q = Question.Role;
.............
.............
int something = (int) q;

Re-

In C#, there are two types of casting:

• Implicit Casting (automatically) - converting a smaller type to a larger type size like-

char -> int -> long -> float -> double

• Explicit Casting (manually) - converting a larger type to a smaller size type like-

double -> float -> long -> int -> char

More can be found in here.

Answer 4

Declare it as a static class having public constants:

public static class Question
{
    public const int Role = 2;
    public const int ProjectFunding = 3;
    public const int TotalEmployee = 4;
    public const int NumberOfServers = 5;
    public const int TopBusinessConcern = 6;
}

And then you can reference it as Question.Role, and it always evaluates to an int or whatever you define it as.

Answer 5

Use:

Question question = Question.Role;
int value = question.GetHashCode();

It will result in value == 2.

This is only true if the enum fits inside an int.

Answer 6

Use an extension method instead:

public static class ExtensionMethods
{
    public static int IntValue(this Enum argEnum)
    {
        return Convert.ToInt32(argEnum);
    }
}

And the usage is slightly prettier:

var intValue = Question.Role.IntValue();