how to compare string list and enum list in c#

Question

My User Class is given below

public class User
    {
        public int Id { get; set; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string Email { get; set; }
        public string UserName { get; set; }
        public Roles Role { get; set; }
        public List<Role> Roles { get; set; }
    }

My Role class is given below

public class Role
    {
        public int Id { get; set; }
        public string RoleName { get; set; }
    }

My enum is given below

public enum Roles
    {
        Admin,
        Guest,
        Accountant
    }

Getting error(Cannot compare string to enum) when compare string with enum values with the code given below

if(User.Roles.Where(m => _roles.Contains(m.RoleName)).ToList()))
    {

    }

=>* here m.RoleName getting error(Cannot compare string to enum)

if you want to compare the Enum name, eg. "Admin" == Role.RoleName, will this help -> https://stackoverflow.com/questions/309333/enum-string-name-from-value — Peter Henry, Feb 04 '21 at 10:10

Enigmativity · Answer 1 · 2021-02-04T21:10:11.920

1

You probably want one of these two variants:

User.Roles.Where(m => _roles.Any(r => r.ToString().Contains(m.RoleName)))

Or:

User.Roles.Where(m => _roles.Contains((Roles)Enum.Parse(typeof(Roles), m.RoleName)))

edited Feb 04 '21 at 21:10

answered Feb 04 '21 at 10:11

Enigmativity

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2

I prefer using generics for parsing `Enum.Parse(m.RoleName)` – Alexey Rumyantsev Feb 04 '21 at 10:12
It is in the if condition – Noufal Feb 04 '21 at 10:19
hai @Enigmativity, it is not working. this is in if condition if(User.Roles.Where(m => _roles.Contains(m.RoleName)).ToList())) { } – Noufal Feb 04 '21 at 10:37
@Noufal - You're saying that the code in your question doesn't work? We knew that already. Have you tried both of my suggestions? I did test both of those before posting. – Enigmativity Feb 04 '21 at 21:09
@AlexeyRumyantsev - The generic parse method for `Enum` is not available in 4.8 or earlier. It's definitely in 5.0. – Enigmativity Feb 04 '21 at 21:14
Enigmativity, yes you are right, but I think .Net Core is mature enough to use it in answers, it is not so hard to figure out how to fallback to non-generic version. – Alexey Rumyantsev Feb 05 '21 at 03:32

score 0 · Answer 2 · answered Feb 04 '21 at 17:56

You can also compare like this:

        if (User.Roles.Any(r=> Enum.GetNames(typeof(Roles)).Contains(r.RoleName)))
        {
            Console.WriteLine("Successed");
        }
        else
        {
            Console.WriteLine("UnAuthrize");
        }

how to compare string list and enum list in c#

2 Answers2