Question

I have this code:

       foreach (var item in ListView1.Items)
            {
                ListView1.Items.Remove(item);
                ListView21.Items.Add(item);
            }

the loop stops at half of the items?

Any idea?

EDIT

Well, maybe it’s my mistake, I need to clarify that this is UltraListView control from Infrajistics, where I can’t add item to another list unless I remove it or clone it from the original list.

But thanks, most of the comments regarding do not modify the list within the loop were correct, so this code works:

           foreach (var item in listView1.Items)
            {
                var i = item.Clone(true);
                listView2.Items.Add(i);
            }
            listView1.Items.Clear();

Thanks,

Answer 1

You cannot modify iterated collection, it should die with exception (or in undefined behavior).
Try making a copy of the array:

   foreach (var item in ListView1.Items.ToArray())
   {
       ListView1.Items.Remove(item);
       ListView21.Items.Add(item);
   }

EDIT:

in fact, your example code can be achieved by writing:

ListView21.Items.AddRange(ListView1.Items);
ListView1.Items.Clear();

(which in fact isn’t EXACTLY what you are doing, but gives the same result and I think it won’t bother you having the same content in both listviews for a moment). The latter is supported since .NET2.0, first solution requires linq, and therefore .NET3.5.