If ComportListbox has an "add" method, why not just use that with a for loop.
foreach ( string portName in ports )
{
ComportListbox.Items.Add( portName );
}
If not, let me know and I will delete this answer.
Otherwise you may have to use a BindingList<string>
. see: Binding List<T> to DataGridView in WinForm
Or you might even have to create an object that contains a string property for the binding name.