private HashSet <object> GetAllowedValues(ValidationContext validationContext)
{
if (AllowedValuesProvider is null)
{
return(AllowedValues.ToHashSet());
}
var instance = validationContext.ObjectInstance;
var type = instance.GetType();
var member = type.GetMember(
AllowedValuesProvider,
MemberTypes.Field | MemberTypes.Property | MemberTypes.Method,
BindingFlags.Instance | BindingFlags.NonPublic | BindingFlags.Public | BindingFlags.Static
)
.FirstOrDefault();
if (member is null)
{
throw new ArgumentException(
$"{nameof(AllowedValuesProvider)} must reference a field or method in {type.FullName}",
AllowedValuesProvider
);
}
var providedValues = member.MemberType switch
{
MemberTypes.Field => ((FieldInfo)member).GetValue(instance),
MemberTypes.Property => ((PropertyInfo)member).GetValue(instance),
MemberTypes.Method => ((MethodInfo)member).Invoke(instance, new object?[] { }),
_ => throw new ArgumentOutOfRangeException(
$"{nameof(AllowedValuesProvider)} is not a valid member on {type.FullName}",
AllowedValuesProvider
)
};
if (providedValues is not IEnumerable <object> providedAllowedValues)
{
throw new ArgumentException(
$"{nameof(AllowedValuesProvider)} on {type.FullName} must implement {nameof(IEnumerable)}",
AllowedValuesProvider
);
}
return(AllowedValues
.Concat(providedAllowedValues)
.ToHashSet());
}
}