How do I create an ArrayList of objects from another class in C#

Question

I am trying to create an ArrayList of instances from another class in my program. In my case the class I am trying to create an ArrayList of is called record with the parameters firstname, lastname, and email. I have created another class called emailList and I am trying to instantiate the array list there. I am getting the error "The non-generic type 'ArrayList' cannot be used with type arguments".

Here is the code I have to create record objects in the Record class:

public class Record
    {
        private String firstname;
        private String lastname;
        private String email;
        public Record(String firstNameIn, String lastNameIn, String emailIn)
        {
            firstname = firstNameIn;
            lastname = lastNameIn;
            email = emailIn;
        }

In the emailList class I am trying to create an ArrayList in the emailList class using:

ArrayList<Record> eList = new ArrayList<Record>;

Was there a problem with your attempt to create an ArrayList? If so, what was it? — Scott Hunter
– Scott Hunter, Commented Jul 13, 2021 at 12:51
ArrayList is a very old class. It's available since .NET framework 1.x where we didn't have generics yet. — Thomas Weller
– Thomas Weller, Commented Jul 13, 2021 at 12:52
Im sorry I am pretty new to coding so bear with me here, but i want the list to contain records in an array not just a regular list. Is there not a difference in the format of the two? — Ryan Carney
– Ryan Carney, Commented Jul 13, 2021 at 12:54
There is not generic ArrayList in .NET, so instead of ArrayList<Record> you probably want List<Record>. Stay away from the old ArrayList. — Tim Schmelter
– Tim Schmelter, Commented Jul 13, 2021 at 12:56
@RyanCarney if you want to use an array, you can do with with var myArray = new Record[3]; myArray[0] = new Record("first", "last", "e-mail"); List<T> uses an array to store items which is expanded when the list reaches its capacity, e.g.: var myList = new List<Record>(); myList.Add(new Record("first", "last", "e-mail")); — Andrei15193
– Andrei15193, Commented Jul 13, 2021 at 12:59

Andrei15193 · Accepted Answer · 2021-07-13 12:51:51Z

2

ArrayList is not generic meaning you cannot provide an generic argument (e.g.: ArrayList<Record>), you need to instantiate it as var eList = new ArrayList();

For type-safe collection check List<T> under System.Collections.Generic namespace.

answered Jul 13, 2021 at 12:51

Andrei15193

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Abstract · Accepted Answer · 2021-07-13 12:55:32Z

1

You don't need a type specifier for ArrayList:

ArrayList eList = new ArrayList();
eList.Add(new Record("Test", "Test", "[email protected]"));

answered Jul 13, 2021 at 12:55

Abstract

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2 Comments

Ryan Carney Over a year ago

even if i am trying to create an array list of objects from a class I created?

Abstract Over a year ago

Nope. Hence new Record("Test", "Test", "[email protected]")

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