prs/prs.desktop/Grids/ContactGrid.cs

using System;
using System.Windows.Controls;
using Comal.Classes;
using InABox.Core;
using InABox.DynamicGrid;

namespace PRSDesktop
{
    public class ContactGrid : DynamicDataGrid<Contact>
    {
        private bool bShowAll;

        public ContactGrid()
        {
            Options.AddRange(
                DynamicGridOption.RecordCount, 
                DynamicGridOption.FilterRows, 
                DynamicGridOption.SelectColumns
            );

            AddButton("Show All", null, ToggleFavourites);
        }

        private bool ToggleFavourites(Button sender, CoreRow[] rows)
        {
            bShowAll = !bShowAll;
            UpdateButton(sender, null, bShowAll ? "Favourites" : "Show All");
            return true;
        }

        protected override void Reload(Filters<Contact> criteria, Columns<Contact> columns, ref SortOrder<Contact> sort,
            Action<CoreTable, Exception> action)
        {
            if (!bShowAll)
                criteria.Add(new Filter<Contact>(x => x.Favourite).IsEqualTo(true));
            base.Reload(criteria, columns, ref sort, action);
        }
    }
}