I'm trying to Create user defined function that handling User tries to add a new user with a duplicate id

and I create this :

public class DuplicateIdException:Exception
{
    public DuplicateIdException(String message) : base(message)
    {

    }
    public override string Message => $" --- {base.Message} --- ";
}

public class TestDuplicateIdException
{

    static void validate(List<Object> Users)
    {
        bool flag = false;
        Type DataType = Users[0].GetType();
        List<DataType> UsersConverter = Users.Cast<DataType>().ToList();
        flag = UsersConverter.Any(x => x.Id == Id);
        if (flag)
        {
            throw new DuplicateIdException("Sorry, You duplicate the Id");
        }
    }
}

I have many objects types and all of them have Id attribute in them, but when i call object.Id it gave an error and not working.. So how can i check them and complete the Exception ?

CodePudding user response：

You can create a base class for all classes that have id ,it can be an interface or base class if you need to.

public class EntityBase
{
    public int Id { get; set; }
}

then inherit/implement it

public class Users : EntityBase
{
    
}
public class Order : EntityBase
{

}

then validate with the base class/interface

public class ValidateDuplidateId
{
    static void Validate(IEnumerable<EntityBase> entities,int id)
    {
        if (entities.Any(x => x.Id == id))
            throw new Exception("Duplicate Id Found");
    }
}

i don't like this approach of throwing exceptions for handling business logic errors, a better approach for me will be something like this

public class Validator
{
    public static bool IsDuplicateId(IEnumerable<EntityBase> entities,int id)
    {
        if (entities.Any(x => x.Id == id))
          return  true;
        return false;
    }
}

then i will add a generic operation result class to handle any type of objects

public class OperationReuslt<T>
{
    public T Result { get; set; }
    public bool Success { get; set; }
    public string Message { get; set; }
}

in my user service ( for example )

 public class UserSerivce
{
    public OperationReuslt<Users>AddUser(int id)
    {
        //replace this with data from your actual data source
        List<Users> users = new List<Users>();

        if(Validator.IsDuplicateId(users,id))
        {
            return new OperationReuslt<Users>
            {
                Success = false,
                Message = "Duplicate UserId"
            };
        }
        // else proceed 
    }
}

you can use this approach as it more readable and doesn't have a performance drawback as the throwing exception approach , but in the end it all depends on your case