Creating a sortable BindingList

Davy Brion — Mon, 10 Sep 2007 11:19:49 +0000

Suppose you want to bind a collection of your custom objects to a DataGridView in a WinForm, and you want it to be sortable without having to write a lot of code. Once again, using Marc Brooks' DynamicComparer this becomes an easy task. Especially when you combine it with the BindingList class (which is a default implementation of the IBindingList interface):

    public class SortableBindingList : BindingList
    {
        private List _sortableList;
 
        public SortableBindingList(List list)
            : base(list)
        {
            _sortableList = list;
        }
 
        protected override bool SupportsSortingCore
        {
            get { return true; }
        }
 
        protected override void ApplySortCore(PropertyDescriptor property,
                                              ListSortDirection direction)
        {
            string sortExpression = property.Name;
 
            if (direction == ListSortDirection.Descending)
            {
                sortExpression = sortExpression + " DESC";
            }
 
            DynamicComparer comparer =
                new DynamicComparer(sortExpression);
 
            _sortableList.Sort(comparer.Comparer);
        }
 
        protected override void RemoveSortCore() {}
    }

Binding a sortable list to a DataGridView is now as easy as this:

            dataGridView.DataSource = new SortableBindingList<Order>(OrderService.GetAllOrders());

Obviously, the sorting capabilities are pretty basic... only one column at a time, sorting can't be removed, etc... For a lot of scenario's though, this could already be sufficient

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Creating a sortable BindingList