public ListBoxDragDropHelper(ListBox draglistbox, ListBox droplistbox, DListBoxDragDropHelperEventListener ondrop)
{
if (draglistbox == null || droplistbox == null)
{
throw new Exception("Null listbox");
}
if (draglistbox.FindForm() != droplistbox.FindForm())
{
throw new Exception("ListBox not on same form");
}
DragListBox = draglistbox;
DropListBox = droplistbox;
OnDrop = ondrop;
DragListBox.MouseDown += DragListBox_MouseDown;
DragListBox.MouseMove += DragListBox_MouseMove;
DragListBox.MouseUp += DragListBox_MouseUp;
DragListBox.QueryContinueDrag += DragListBox_QueryContinueDrag;
DragListBox.GiveFeedback += DragListBox_GiveFeedback;
DropListBox.DragOver += DropListBox_DragOver;
DropListBox.DragDrop += DropListBox_DragDrop;
DropListBox.DragLeave += DropListBox_DragLeave;
}