C# How to add an item to a listview if the item exists but the subitem is different?

Question

I have a listview with 2 columns, and I have a button on the form where the user enters and ip:port and then it adds the item to the listview when he clicks the button, pretty basic.

What I want to do is:
when the user clicks the button, I want to check if the ip exists in the listview, and if it does, I then want to check if the port associated with that ip exists in the subitem. If it doesn't I want to add the item, that way I would have for example 2 items with the same IP, but with different ports.

Any help would be appreciated, thanks in advance!

Answer 1

Try this:

void Main()
{
    Form form = new Form();

    ListView lv = new ListView();
    lv.View = View.Details;
    lv.Columns.Add(new ColumnHeader() { Name = "ip", Text = "IP Address" });
    lv.Columns.Add(new ColumnHeader() { Name = "port", Text = "Port" });
    lv.Dock = DockStyle.Fill;

    // Tests.
    AddItem(lv, "10.0.0.1", String.Empty);
    AddItem(lv, "10.0.0.2", String.Empty);
    AddItem(lv, "10.0.0.1", "8080");
    AddItem(lv, "10.0.0.1", String.Empty);
    AddItem(lv, "10.0.0.1", "8080");

    form.Controls.Add(lv);
    form.ShowDialog();
}

private void AddItem(ListView listView, string ip, string port)
{
    var items = listView.Items.Cast<ListViewItem>();
    // First subitem starts at index 1.
    bool exists = items.Where(item =>
        (item.Text == ip && item.SubItems[1].Text == port)).Any();
    if (!exists)
    {
        var item = new ListViewItem(ip);
        item.SubItems.Add(new ListViewItem.ListViewSubItem(item, port));
        listView.Items.Add(item);
    }
    else
    {
        Console.WriteLine("Duplicate: {0}:{1}", ip, port);
    }
}

The check is in the AddItem() method. Modify according to your requirements.