Question on Lists

[Webskater]

I asked a question the other day on this subject, but I think I made it too complicated.

In my DataObjects class I have a class called User. Which, to keep things simple, let's say looks like this.

public class User
{
private int _UserID;
        public int UserID
        {
            get { return _UserID; }
            set { _UserID = value; }
        }
        public string UserName
        {
            get { return _UserName; }
            set { _UserName = value; }
        }
}

In my DataAccess class I want to return a list of users, so I might have this:

public List<DataObjects.User> getUsers()
    {
        List<DataObjects.Event> myUsersList = new List<DataObjects.Event>();
        SqlConnection myConnection = new SqlConnection(connectionString);
        SqlCommand myCommand = myConnection.CreateCommand();
        SqlDataReader dr;
        myCommand.CommandText = "getUsers";
        myCommand.CommandTimeout = 120;
        myCommand.Connection = myConnection;
        myCommand.CommandType = CommandType.StoredProcedure;

        myConnection.Open();
        dr = myCommand.ExecuteReader(CommandBehavior.CloseConnection);

        if (dr.HasRows)
        {
            while (dr.Read())
            {
                DataObjects.User myUser = new DataObjects.User();
                myUser.UserID = (dr["UserID"] == null) ? 0 : Convert.ToInt32(dr["UserID"].ToString());
                myUser.UserName = (dr["UserName"] == null) ? "" : dr["UserName"].ToString();
                myUsersList.Add(myUser);
            }
        }

        return myUsersList;
    }

And, on any .aspx page I can get my list of users by writing this:

DataAccess da = new DataAccess();
List<DataObjects.User> myUsersList = new List<DataObjects.User>();
myUsersList = da.getUsers();
gvUsers.DataSource = myUsersList;
gvUsers.DataBind();

Which all works fine.

So, my question is ... what does the code snippet mean in the context of the Data Objects class? I have a User Object and I can create a list of UserObjects easily enough (as above) ... so what does the code below mean or represent?

public class UsersList : List<User>
    {

    }

I assumed it was effective a sort of shortcut so that, for example, in the DataAccess class instead of creating the List like this ..

List<DataObjects.Event> myUsersList = new List<DataObjects.Event>();

... I thought you might be able to create it (something) like this:

UsersList myUsersList - new List<UsersList>;

... but all I get are syntax errors. Have I missed something fundamental here?

Thanks for any help.

[stlaural]

public class UsersList : List<User>
    {

    }

This means you are creating a new class that Inherits from List<User> so instead of instantiating a new List<UsersList> I think you should instantiate a new UsersList and have a constructor in this new class.

UsersList myUsersList = new UsersList();

Also, you need an equal sign '=' not a minus sign '-' and the parenthesis at the end But I'm pretty sure this was not the source of your error anyway.

UsersList myUsersList - new List<UsersList>;

.

[Webskater]

public class UsersList : List<User>
    {

    }

This means you are creating a new class that Inherits from List<User> so instead of instantiating a new List<UsersList> I think you should instantiate a new UsersList and have a constructor in this new class.

When you say 'have a constructor in this new class' ... like this?

public class UsersList : List<User>
    {
        UsersList myUsersList = new UsersList();
    }

I tried doing that and then put this on a .aspx page ...

UsersList myUsersList = new List<UsersList>();

but when I try to run it I get this ...

Cannot implicitly convert type 'System.Collections.Generic.List<DataObjects.UsersList>' to 'DataObjects.UsersList'

Thanks for your help. (The minus sign etc. were typos - I typed the code up changing it to be about 'Users' just to make it more generic.)