IEnumerator

Question

hello I need to do something like this: class myClass { string name; } List l = new List (); l.getEnumerator(); foreach (; l.movenext(); ) { print ( l.Current.name); } How to use IEnumerator to access the fields of the classes? thanks.

Alan · Answer

If you don't have to use IEnumerator then you can simply use the generic List's IndexOf() method to find the index (zero-based) of a given object: int index = l.IndexOf(c); Notice that if the same object is added more than once to the List then IndexOf() returns the index of the first such object.

Marco · Answer

sorry but this doesn't solve my problem: class myclass { public myclass { } } //main myclass abcd; List l= new ........ l.Add(a); l.Add(b); l.Add(c); l.Add(d); int index = c.getPositionInList(); Is there a way to retrieve index? thanks.

Alan · Answer

You can't stop MoveNext() starting from the beginning (i.e. an index of 0) but you can skip the first 6 iterations using this code: for (int i = 0 ;ie.MoveNext(); i++) { if (i if (ie.Current.Name.ToLower() == marco) { index = i; break; } }

Marco · Answer

but a way to do this is there? ie+6 //avoid movenext() for 6 times; ?

Alan · Answer

As the List.Enumerator class (the underlying IEnumerator for the List class) doesn't expose an 'Index' property then the best way to do this is to count the elements yourself: IEnumerator ie = l.GetEnumerator(); int index = -1; for (int i = 0 ;ie.MoveNext(); i++) { if (((myClass)ie.Current).Name.ToLower() == marco) { index = i; break; } } Console.WriteLine(index); // 0 Incidentally you can avoid having to cast the IEnumerator to myClass by using the generic interface IEnumerator instead: IEnumerator ie = l.GetEnumerator(); int index = -1; for (int i = 0 ;ie.MoveNext(); i++) { if (ie.Current.Name.ToLower() == marco) { index = i; break; } } Console.WriteLine(index); // 0

Marco · Answer

thanks a lot! And if I wanna do this how to do? for ( ;ie.MoveNext(); ) { if ((myClass)ie.Current).Name == marco int index = (int) ie; } Is there a way ?

Alan · Answer

Try this: using System; using System.Collections; using System.Collections.Generic; class Program { static void Main() { List l = new List (); myClass m = new myClass(); m.Name = Marco; l.Add(m); m = new myClass(); m.Name = Alan; l.Add(m); IEnumerator ie = l.GetEnumerator(); for ( ;ie.MoveNext(); ) { Console.WriteLine(((myClass)ie.Current).Name); } Console.ReadKey(); } } public class myClass { string name; public string Name { get {return name;} set {name = value;} } }