how do i prevent multiple instances of added rows in a listview?

Question

Hi. Here's my code:

List<ListViewItem> itemsToMove = new List<ListViewItem>();
foreach (ListViewItem item in lvScanRepository.SelectedItems)
{
    itemsToMove.Add(item);
}

foreach (ListViewItem item in itemsToMove)
{
    if (!lvBatch.Items.Contains(item))
    {
        lvScanRepository.Items.Remove(item);
        lvBatch.Items.Add(item);
    }
}

Answer 1

A ListViewItem can't belong to more than one ListView at the same time, so this condition:

if (!lvBatch.Items.Contains(item))

... will always be true.

What criteria do you want to use to determine whether the item in one ListView is "similar" to an item in another? Depending on that, you have a couple of options:

ListViewItem has a property called Name which can be used to uniquely identify items in a ListView. You can then call Items.ContainsKey(String) to see if an item exists with that name.

Alternatively you can search in lvBatch to find an item with the same Text as the one you're trying to add:

if (!lvBatch.Items.Cast<ListViewItem>().Any(i => i.Text == item.Text))

(You need to cast because ListViewItemCollection doesn't actually implement IEnumerable<ListViewItem>.)