如何在C＃中检查参数是否与枚举中的值匹配？

Question

I have this enum:

public enum ContentKey {
    Menu = 0,
    Article = 1,
    FavoritesList = 2
};

This action method:

public ActionResult Edit(string pk, string rk, int row = 0) {
    try {
        var content = _contentService.Get(pk, rk);

The following class Content which is based on the TableServiceEntity . Note that TableServiceEntity is common to all my data classes.

public class Content : TableServiceEntity 
{

public abstract class TableServiceEntity
{
    protected TableServiceEntity();
    protected TableServiceEntity(string partitionKey, string rowKey);
    public virtual string PartitionKey { get; set; }

Is there a way I can check the value of pk matches one of the enum values? What I am not sure about is how I can check this. I assume I need to have the check in the Content class but I am not sure how to override the virtual string and throw an exception when there's no match.

Update : If possible I would like to do this in the Content class get set but I am not sure how to add a get set to this class.

Answer 1

You can use Enum.IsDefined to see if a string matches an Enum value:

public enum ContentKey
{
    Menu = 0,
    Article = 1,
    FavoritesList = 2
}

static bool Check(string pk)
{
    return Enum.IsDefined(typeof(ContentKey), pk);
}

static void Main(string[] args)
{
    Console.WriteLine(Check("Menu"));
    Console.WriteLine(Check("Foo"));
}

You can also define a setter that does not set the backing field unless the new value is defined the enum:

class Foo
{
    private string pk;

    public string PK
    {
        get
        {
            return this.pk;
        }
        set
        {
            if(Enum.IsDefined(typeof(ContentKey), value))
            {
                this.pk = value;
            }
            else
            {
                throw new ArgumentOutOfRangeException();
            }
        }
    }
}

This is a non-automatic property where you define the backing field yourself. The new value is accessible via the value keyword.

Answer 2

You can use Enum.Parse() :

ContentKey key = (ContentKey) Enum.Parse(typeof(ContentKey), pk);

It will throw an ArgumentException if pk does not match any named constant defined in ContentKey .

Answer 3

Try this.

if(Enum.IsDefined(typeof(ContentKey),pk))
{
   //Do your work;
}