为了确保枚举值存在，然后解析它，还可以执行以下操作。

// Fake Day of Week
string strDOWFake = "SuperDay";

// Real Day of Week
string strDOWReal = "Friday";

// Will hold which ever is the real DOW.
DayOfWeek enmDOW;

// See if fake DOW is defined in the DayOfWeek enumeration.
if (Enum.IsDefined(typeof(DayOfWeek), strDOWFake))
{
    // This will never be reached since "SuperDay"
    // doesn't exist in the DayOfWeek enumeration.
    enmDOW = (DayOfWeek)Enum.Parse(typeof(DayOfWeek), strDOWFake);
}
// See if real DOW is defined in the DayOfWeek enumeration.
else if (Enum.IsDefined(typeof(DayOfWeek), strDOWReal))
{
    // This will parse the string into it's corresponding DOW enum object.
    enmDOW = (DayOfWeek)Enum.Parse(typeof(DayOfWeek), strDOWReal);
}

// Can now use the DOW enum object.
Console.Write("Today is " + enmDOW.ToString() + ".");

最近，我不再在代码中使用枚举，而是使用带有受保护构造函数和预定义静态实例的类（感谢Roelof-C#确保有效枚举值-Futureproof方法）。

鉴于此，下面是我现在如何处理这个问题（包括隐式转换为int或从int转换）。

public class Question
{
    // Attributes
    protected int index;
    protected string name;
    // Go with a dictionary to enforce unique index
    //protected static readonly ICollection<Question> values = new Collection<Question>();
    protected static readonly IDictionary<int,Question> values = new Dictionary<int,Question>();

    // Define the "enum" values
    public static readonly Question Role = new Question(2,"Role");
    public static readonly Question ProjectFunding = new Question(3, "Project Funding");
    public static readonly Question TotalEmployee = new Question(4, "Total Employee");
    public static readonly Question NumberOfServers = new Question(5, "Number of Servers");
    public static readonly Question TopBusinessConcern = new Question(6, "Top Business Concern");

    // Constructors
    protected Question(int index, string name)
    {
        this.index = index;
        this.name = name;
        values.Add(index, this);
    }

    // Easy int conversion
    public static implicit operator int(Question question) =>
        question.index; //nb: if question is null this will return a null pointer exception

    public static implicit operator Question(int index) =>        
        values.TryGetValue(index, out var question) ? question : null;

    // Easy string conversion (also update ToString for the same effect)
    public override string ToString() =>
        this.name;

    public static implicit operator string(Question question) =>
        question?.ToString();

    public static implicit operator Question(string name) =>
        name == null ? null : values.Values.FirstOrDefault(item => name.Equals(item.name, StringComparison.CurrentCultureIgnoreCase));


    // If you specifically want a Get(int x) function (though not required given the implicit converstion)
    public Question Get(int foo) =>
        foo; //(implicit conversion will take care of the conversion for you)
}

这种方法的优点是你可以从枚举中得到所有的东西，但是你的代码现在更灵活了，所以如果你需要根据Question的值执行不同的操作，你可以将逻辑放入Question本身（即以首选的OO方式），而不是在代码中放入大量的case语句来处理每个场景。

注意：2018-04-27更新了答案，以利用C#6功能；即声明表达式和lambda表达式体定义。原始代码参见修订历史。这样做的好处是使定义不那么冗长；这是对这个答案方法的主要抱怨之一。

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

…是一个很好的声明。

您必须将结果强制转换为int，如下所示：

int Question = (int)QuestionType.Role

否则，类型仍然是QuestionType。

这种严格程度是C#的方式。

一种替代方法是改用类声明：

public class QuestionType
{
    public static int Role = 2,
    public static int ProjectFunding = 3,
    public static int TotalEmployee = 4,
    public static int NumberOfServers = 5,
    public static int TopBusinessConcern = 6
}

声明不那么优雅，但不需要将其转换为代码：

int Question = QuestionType.Role

或者，您可能会对Visual Basic感到更舒服，它在许多方面都满足了这种期望。

将其声明为具有公共常量的静态类：

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;
}

然后，您可以将其引用为Question.Role，它的计算结果始终为int或您定义的任何值。

你应该使用我们可以在任何其他语言中使用的类型铸造。

如果枚举是这样的-

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

你需要转换为int，然后这样做-

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

Re-

在C#中，有两种类型的铸件：

隐式转换（自动）-将较小的类型转换为较大的类型大小，如-

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

显式转换（手动）-将较大的类型转换为较小的类型，如-

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

更多信息可以在这里找到。

也许我错过了，但有人尝试过简单的通用扩展方法吗？

这对我来说非常有用。您可以通过这种方式避免API中的类型转换，但最终会导致更改类型操作。这是对Roslyn编程的一个很好的例子，让编译器为您生成GetValue＜T＞方法。

    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;
    }
}