How to refresh data grid with new search results with MVVM Light - mvvm-light

Question

I'm using the latest MMVM Light windows 8 binaries and VS 2012 latest updates, so all is good there. I'm new to the MVVM Light framework, so it's an adjustment.
I have a Customers page with a grid that is searched with a textbox and button - the text box is bound and the button uses a command. The data is showing up in the view model just fine. I LINQ over the Customers List and set the Customers list property - all works well. The problem is, the page doesn't refresh. When I go to another page and return to the Customers page, the searched data is displayed.
I suspect the view model is static and needs to re-instantiated.
The follow are the respective code frags:
public partial class ViewModelLocator
{
static ViewModelLocator()
{
ServiceLocator.SetLocatorProvider(() => SimpleIoc.Default);
if (ViewModelBase.IsInDesignModeStatic)
{
SimpleIoc.Default.Register<IDataService, Design.DesignDataService>();
}
else
{
SimpleIoc.Default.Register<IDataService, DataService>();
}
// Services
SimpleIoc.Default.Register<INavigationService, NavigationService>();
SimpleIoc.Default.Register<IMessenger, Messenger>();
// View Models
SimpleIoc.Default.Register<MainViewModel>();
SimpleIoc.Default.Register<CustomersViewModel>();
SimpleIoc.Default.Register<CustomerViewModel>(true);
SimpleIoc.Default.Register<ContactsViewModel>();
}
public MainViewModel Main
{
get
{
return ServiceLocator.Current.GetInstance<MainViewModel>();
}
}
public CustomersViewModel Customers
{
get
{
return ServiceLocator.Current.GetInstance<CustomersViewModel>();
}
}
public CustomerViewModel Customer
{
get
{
return ServiceLocator.Current.GetInstance<CustomerViewModel>();
}
}
public ContactsViewModel Contacts
{
get
{
return ServiceLocator.Current.GetInstance<ContactsViewModel>();
}
}
public static void Cleanup()
{
}
}
}
public class CustomersViewModel : ViewModelBase
{
private readonly IDataService _dataService;
private INavigationService _navigationService;
private IMessenger _messenger;
public RelayCommand<string> RefreshClickCommand { get; set; }
public RelayCommand<string> SearchCustomersCommand { get; set; }
public const string CustomersPropertyName = "Customers";
private ObservableCollection<Customer> _customers = null;
public ObservableCollection<Customer> Customers
{
get
{
return _customers;
}
set
{
if (_customers == value)
{
return;
}
_customers = value;
RaisePropertyChanging(CustomersPropertyName);
}
}
public const string WelcomeTitlePropertyName = "WelcomeTitle";
private string _welcomeTitle = string.Empty;
public string WelcomeTitle
{
get
{
return _welcomeTitle;
}
set
{
if (_welcomeTitle == value)
{
return;
}
_welcomeTitle = value;
RaisePropertyChanged(WelcomeTitlePropertyName);
}
}
public const string CustomerSearchTermPropertyName = "CustomerSearchTerm";
private string _customerSearchTerm = string.Empty;
public string CustomerSearchTerm
{
get
{
return _customerSearchTerm;
}
set
{
if (_customerSearchTerm == value)
{
return;
}
_customerSearchTerm = value;
RaisePropertyChanging(CustomerSearchTermPropertyName);
}
}
public Customer SelectedItem
{
set
{
Customer customer = value;
_messenger.Send<Customer>(customer, "Customer");
_navigationService.Navigate(typeof(CustomerPage));
}
}
public CustomersViewModel(IDataService dataService)
{
_navigationService = SimpleIoc.Default.GetInstance<INavigationService>();
_messenger = SimpleIoc.Default.GetInstance<IMessenger>();
_dataService = dataService;
_dataService.GetData(
(item, error) =>
{
if (error != null)
{
// Report error here
return;
}
WelcomeTitle = item.Title + "Customers";
});
GetCustomers();
InitializeCommands();
}
private void InitializeCommands()
{
RefreshClickCommand = new RelayCommand<string>((item) =>
{
GetCustomers();
});
SearchCustomersCommand = new RelayCommand<string>((item) =>
{
SearchCustomers();
});
}
private void GetCustomers()
{
_customers = _dataService.GetCustomers();
}
private void SearchCustomers()
{
var cust = _dataService.GetCustomers();
List<Customer> customers = (from c in cust
where c.CompanyName.StartsWith(_customerSearchTerm)
orderby c.CompanyName
select c).ToList();
_customers = new ObservableCollection<Customer>(customers);
}
}
<common:LayoutAwarePage x:Class="SalesAccountManager.Views.RelationshipManager.CustomersPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:common="using:SalesAccountManager.Common"
xmlns:ignore="http://www.ignore.com"
xmlns:telerikGrid="using:Telerik.UI.Xaml.Controls.Grid"
xmlns:WinRtBehaviors="using:WinRtBehaviors"
xmlns:Win8nl_Behavior="using:Win8nl.Behaviors"
mc:Ignorable="d ignore"
d:DesignHeight="768"
d:DesignWidth="1366"
DataContext="{Binding Customers, Source={StaticResource Locator}}">
....
<Grid>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Left">
<TextBlock Text="Customers" FontFamily="Segoe UI" FontSize="38"/>
</StackPanel>
<StackPanel Orientation="Horizontal" HorizontalAlignment="Right" Margin="0, 0, 100, 0">
<TextBox Height="20" Width="600" Background="White" Text="{Binding CustomerSearchTerm, Mode=TwoWay}" />
<Button Background="White" Command="{Binding SearchCustomersCommand}">
<Image Source="../../Images/Search.jpg" Height="20" Width="20"></Image>
</Button>
</StackPanel>
</Grid>
Any guidance on this would be appreciated...
Thanks!