Dynamic LINQ to Entities Queries Using WCF/WPF Demo Code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using WpfClient.ServiceProxy;
using System.ServiceModel;
using WpfClient.ServiceReference;

using FluidKit.Controls;
using System.Diagnostics;
using WpfClient.Commands;




namespace WpfClient
{
    /// <summary>
    /// Contains a view of some Northwind Customers within
    /// Pavan Podilas excellent ElementFlow. Also show
    /// associated Orders for the selected Customer
    /// </summary>
    public partial class CustomerOrdersWindow : Window
    {
        #region Data
        private CustomerOrdersViewModel viewModel = new CustomerOrdersViewModel();
        private RelayCommand searchCommand;
        private RelayCommand diagCommand;
        private ElementFlow elementFlow;
        private int viewIndex;
        private ViewStateBase[] views = {
		                                 	new CoverFlow(),
		                                 	new Carousel(),
		                                 	new RollerCoaster(),
		                                 	new Rolodex(),
		                                 };
        #endregion

        #region Ctor
        public CustomerOrdersWindow()
        {
            InitializeComponent();
            this.DataContext = viewModel;
            this.Loaded += Window1_Loaded;
            this.btnSearch.Command = this.SearchCommand;
            this.btnDiagnostics.Command = this.DiagCommand;
        }
        #endregion

        #region Commands
        public RelayCommand SearchCommand
        {
            get
            {
                if (searchCommand == null)
                {
                    searchCommand = new RelayCommand(
                        param => { return true; },
                        param =>
                        {
                            DoSearch();
                        }
                        );
                }
                return searchCommand;
            }
        }


        public RelayCommand DiagCommand
        {
            get
            {
                if (diagCommand == null)
                {
                    diagCommand = new RelayCommand(
                        param => { return true; },
                        param =>
                        {
                            DoDiagnostics();
                        }
                        );
                }
                return diagCommand;
            }
        }
        #endregion

        #region Private Methods
        private void ElementFlowSetup()
        {
            // Get reference to ElementFlow
            DependencyObject obj = VisualTreeHelper.GetChild(lstCustomers, 0);
            while ((obj is ElementFlow) == false)
            {
                obj = VisualTreeHelper.GetChild(obj, 0);
            }
            elementFlow = obj as ElementFlow;

            elementFlow.SelectedIndexChanged += EFSelectedIndexChanged;
            elementFlow.SelectedIndex = 0;
        }

        private void Window1_Loaded(object sender, RoutedEventArgs e)
        {

            ElementFlowSetup();
            viewModel.FetchDefaultCustomerWithOrders();
            custControl.BoundCustomer = viewModel.SelectedCustomer;
            custOrdersControl.BoundCustomer = viewModel.SelectedCustomer;
            searchControl.BoundType = typeof (Customers);
        }


        private void EFSelectedIndexChanged(object sender, EventArgs e)
        {
            if (viewModel != null && viewModel.CurrentCustomers.Count > 0)
            {
                try
                {
                    //Get selected customer to show from ElementFlow
                    viewModel.SelectedCustomer =
                        viewModel.CurrentCustomers[(sender as ElementFlow).SelectedIndex];
                    custControl.BoundCustomer = viewModel.SelectedCustomer;
                    custOrdersControl.BoundCustomer = viewModel.SelectedCustomer;
                }
                catch { }
            }
        }


        private void DoSearch()
        {
            searchControl.Visibility = Visibility.Visible;
            searchControl.Initialise();
            searchControl.SearchRequested += searchControl_SearchRequested;    
        }

        private void searchControl_SearchRequested(object sender, SearchEventArgs e)
        {
            if (searchControl.Visibility == Visibility.Visible)
            {
                searchControl.Visibility = Visibility.Hidden;
                viewModel.SearchCustomerWithOrders(e.WhereClause, e.SearchParameters);
            }
        }

  

        private void DoDiagnostics()
        {
            DiagnosticsWindow diagWin = new DiagnosticsWindow();
            diagWin.ShowInTaskbar = false;
            diagWin.WindowStartupLocation = WindowStartupLocation.CenterOwner;
            diagWin.Owner = this;
            diagWin.ShowDialog();
        }
        #endregion

        #region Overrides
        protected override void OnKeyDown(KeyEventArgs e)
        {
            if (e.Key == Key.F12)
            {
                viewIndex = (viewIndex + 1) % views.Length;
                elementFlow.CurrentView = views[viewIndex];
            }
        }
        #endregion
    }
}