Question

I am working on win-form app that has .net 2.0 as framework. I have a list of an class in which i would like to check if the object already exist before adding it in list. I know i can use .Any of linq to do this but it does not work in my situation. I can not use .contains since the object will not be same as it has lot of properties , so I am left with a unique property to check if it is already added,but it is not working Code:

bool alreadyExists = exceptionsList.Exists(item =>
       item.UserDetail == ObjException.UserDetail    
    && item.ExceptionType != ObjException.ExceptionType) ;

My class

public class AddException
    {
        public string  UserDetail{ get; set; }
        public string  Reason { get; set; }
        public Enumerations.ExceptionType ExceptionType { get; set; }

    }
    public class Enumerations
    {
        public enum ExceptionType
        {
            Members = 1,
            Senders =2
        }
    }

Iniial situation

AddException objException = new AddException
                {
                    Reason = "test",
                    UserDetail = "Ankur",
                    ExceptionType = 1
                };

this object is added in list.

Second time

AddException objException = new AddException
                {
                    Reason = "test 1234",
                    UserDetail = "Ankur",
                    ExceptionType = 1
                };

this should not be getting added in the list , but the .Exist check is failing and it is getting added in the list.

Any suggestions.

Answer 1

Exists returns already the bool and not an object, so your null check at the end doesn’t work.

bool alreadyExists = exceptionsList.Exists(item =>
        item.UserDetail == ObjException.UserDetail
     && item.ExceptionType == ObjException.ExceptionType
);

The important part is, you have to change

item.ExceptionType != ObjException.ExceptionType

to

item.ExceptionType == ObjException.ExceptionType

since you want to know if there are items which are equal by UserDetail and ExceptionType.

Also note that you should not initialize Enums with their int-value. So change

AddException objException = new AddException
{
    Reason = "test 1234",
    UserDetail = "Ankur",
    ExceptionType = 1
};

to

AddException objException = new AddException
{
    Reason = "test 1234",
    UserDetail = "Ankur",
    ExceptionType = Enumerations.ExceptionType.Members
};

(By the way, that should not even compile)