Question

Hello how can i remove item from generic list here is my code im trying to do it right but i dont know where i make mistake;/

Users us_end = new Users();
foreach (var VARIABLE in ((List<Users>)Application["Users_On"]))
{
    if(VARIABLE.Id == (int)Session["Current_Id"])
    {
        us_end.Name = VARIABLE.Name;
        us_end.Id = VARIABLE.Id;
        us_end.Data = VARIABLE.Data;
    }
}
List<Users> us = ((List<Users>)Application["Users_On"]);
us.Remove(us_end);
Application["Users_On"] = us;

Answer 1

You have to get the same object to remove, not a copy.

Users us_end;

foreach (var VARIABLE in ((List<Users>)Application["Users_On"]))
{
    if(VARIABLE.Id == (int)Session["Current_Id"])
    {
       us_end = (Users)VARIABLE;
       break;
    }
}

if (us_end != null)
{
    List<Users> us = ((List<Users>)Application["Users_On"]);
    us.Remove(us_end);
    Application["Users_On"] = us;
}

Edit:

Just to clarify an address here, as pst pointed, you could also implement the IEquatable interface and some overridings like on the Groo’s answer to make it work, but i think it’s overkill on this specific subject. Giving this as the most common practice, but making clear that it’s also possible to remove items from a list, even if they are diferent instances or even diferent objects with a technique like that.

Ref.: http://msdn.microsoft.com/en-us/library/ms131187.aspx