Json.Net and validation of Enums in Web API

Question

I'm writing a web api in .Net Core 2.2. I have an enumeration as follows:

using System.Runtime.Serialization;

namespace MyNamespace
{
    public enum MyEnum
    {
        [EnumMember(Value = "Some Value")]
        SomeValue
    }
}

If I pass in random data as MyEnum in a request using the enum I rightly get an error, but if I pass "Some Value" or "SomeValue" it passes. How do I make "SomeValue" invalid? "SomeValue" isn't in my swagger and isn't a value I want to accept.

So basically, model validation passes for "SomeValue" when that isn't really valid.

Any ideas how I can make only "Some Value" valid? Thanks

Amin Golmahalleh · Answer 1 · 2019-11-23T07:52:45.973

If I Understand Correctly the Question.You Can Use This Sample For Get 'Some Value' Instead Of 'SomeValue':

using System.ComponentModel;

 public enum MyEnum
    {
        [Description("Some Value")]
        SomeValue
    }

Create StringEnumExtension Class :

public static class StringEnumExtension
    {
        public static string GetDescription<T>(this T e) 
        {
            string str = (string) null;

            if ((object) e is Enum)
            {
                Type type = e.GetType();
                foreach (int num in Enum.GetValues(type))
                {
                    if (num == Convert.ToInt32(e, CultureInfo.InvariantCulture))
                    {
                        object[] customAttributes = type.GetMember(type.GetEnumName((object) num))[0]
                            .GetCustomAttributes(typeof(DescriptionAttribute), false);
                        if ((uint) customAttributes.Length > 0U)
                        {
                            str = ((DescriptionAttribute) customAttributes[0]).Description;
                        }

                        break;
                    }
                }
            }

            return str;
        }
    }

Then Use the Code Below to Call :

 var result = MyEnum.SomeValue.GetDescription();

Hi, no I think I've confused you. When submitting a request in a web api both "SomeValue" and "Some Value" are valid in the request. — user2883072, Nov 20 '19 at 13:02

score 0 · Answer 2 · answered Nov 20 '19 at 15:42

0

I've had similar problems with Enums in the past, even with the EnumMember attribute and the default StringEnumConverter.

I ended up with a custom converter that inherits from StringEnumConverter which reads EnumMember and parses the given string value to the enum member: https://stackoverflow.com/a/58338955/225808

I've tested my code with additional spaces and I get validate errors when using my code. I anonymized my code and this should work for you:

[Required(ErrorMessage = "weather requires a valid value")]
[JsonProperty("weather")]
public WeatherEnum? Weather { get; set; }

answered Nov 20 '19 at 15:42

citronas

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Hi, am I missing something, but CanConvert never gets called, – user2883072 Dec 10 '19 at 14:00
Yes. I did not link any code with `CanConvert`. Please refer to the code of my linked question and combine it with the code I wrote in this answer. – citronas Dec 10 '19 at 16:58
Hi citronas... I looked at your code but CanConvert never triggers in my effort. Are you sure it's triggered if decorating properties? – user2883072 Dec 10 '19 at 21:01
Please show me the code with `CanConvert`. I can't find it – citronas Dec 11 '19 at 10:35

Json.Net and validation of Enums in Web API

2 Answers2

Linked