Is there out-of-the box validator for Enum values in DataAnnotations namespace?

Question

C# enum values are not limited to only values listed in it\'s definition and may store any value of it\'s base type. If base type is not defined than Int32 or s

Answer 1

There's EnumDataType in .NET4+ ...

Make sure you set the 3rd parameter, validateAllProperties=true in the call to ValidateObject

so from your example:

public class Entity
{
    [EnumDataType(typeof(MyEnum))]
    public MyEnum EnumValue { get; set; }
}

[Fact]
public void TestInvalidEnumValue()
{
    Entity entity = new Entity { EnumValue = (MyEnum)(-126) };
    // -126 is stored in the entity.EnumValue property

    Assert.Throws<ValidationException>(() =>
        Validator.ValidateObject(entity, new ValidationContext(entity, null, null), true));
}

Answer 2

What you're looking for is:

 Enum.IsDefined(typeof(MyEnum), entity.EnumValue)

[Update+1]

The out of the box validator that does a lot of validations including this one is called EnumDataType. Make sure you set validateAllProperties=true as ValidateObject, otherwise your test will fail.

If you just want to check if the enum is defined, you can use a custom validator with the above line:

    [AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Field | AttributeTargets.Property | AttributeTargets.Method, AllowMultiple = false)]
    public sealed class EnumValidateExistsAttribute : DataTypeAttribute
    {
        public EnumValidateExistsAttribute(Type enumType)
            : base("Enumeration")
        {
            this.EnumType = enumType;
        }

        public override bool IsValid(object value)
        {
            if (this.EnumType == null)
            {
                throw new InvalidOperationException("Type cannot be null");
            }
            if (!this.EnumType.IsEnum)
            {
                throw new InvalidOperationException("Type must be an enum");
            }
            if (!Enum.IsDefined(EnumType, value))
            {
                return false;
            }
            return true;
        }

        public Type EnumType
        {
            get;
            set;
        }
    }

... but I suppose it's not out of the box then is it?