public override bool IsEnumDefined(object value)
{
if (value == null)
{
throw new ArgumentNullException(nameof(value));
}
if (!IsEnum)
{
throw new ArgumentException(SR.Arg_MustBeEnum, "enumType");
}
// Check if both of them are of the same type
RuntimeType valueType = (RuntimeType)value.GetType();
// If the value is an Enum then we need to extract the underlying value from it
if (valueType.IsEnum)
{
if (!valueType.IsEquivalentTo(this))
{
throw new ArgumentException(SR.Format(SR.Arg_EnumAndObjectMustBeSameType, valueType, this));
}
valueType = (RuntimeType)valueType.GetEnumUnderlyingType();
}
// If a string is passed in
if (valueType == StringType)
{
// Get all of the Fields, calling GetHashEntry directly to avoid copying
string[] names = Enum.InternalGetNames(this);
return(Array.IndexOf(names, value) >= 0);
}
// If an enum or integer value is passed in
if (IsIntegerType(valueType))
{
RuntimeType underlyingType = Enum.InternalGetUnderlyingType(this);
if (underlyingType != valueType)
{
throw new ArgumentException(SR.Format(SR.Arg_EnumUnderlyingTypeAndObjectMustBeSameType, valueType, underlyingType));
}
ulong[] ulValues = Enum.InternalGetValues(this);
ulong ulValue = Enum.ToUInt64(value);
return(Array.BinarySearch(ulValues, ulValue) >= 0);
}
else
{
throw new InvalidOperationException(SR.InvalidOperation_UnknownEnumType);
}
}