public MainWindow()
        {
            InitializeComponent();
            var context = new EntityFrameworkIssues.Issues.IssuesContext();
            var source  = new DevExpress.Data.Linq.EntityServerModeSource
            {
                KeyExpression   = nameof(EntityFrameworkIssues.Issues.Issue.Id),
                QueryableSource = context.Issues.AsNoTracking()
            };

            grid.ItemsSource = source;
            LoadLookupData();
        }
        public MainWindow()
        {
            InitializeComponent();
            var source = new DevExpress.Data.Linq.EntityInstantFeedbackSource
            {
                KeyExpression = nameof(EntityFrameworkIssues.Issues.Issue.Id)
            };

            source.GetQueryable += (sender, e) =>
            {
                var context = new EntityFrameworkIssues.Issues.IssuesContext();
                e.QueryableSource = context.Issues.AsNoTracking();
            };
            grid.ItemsSource = source;
            LoadLookupData();
        }
        void LoadLookupData()
        {
            var context = new EntityFrameworkIssues.Issues.IssuesContext();

            usersLookup.ItemsSource = context.Users.Select(user => new { Id = user.Id, Name = user.FirstName + " " + user.LastName }).ToArray();
        }