WPF ListView selection upon focus lost - wpf

Question

I am currently learning and working on simple WPF (MVVM pattern) application, which allows to select items from one listview (available items) to another (order) and create an order class instance once 'buy' button is being pressed.
My problem is that once I click on first listview - item is selected and I am not able to deselect it once focus is lost.
I have learnt a lot about event and commands in MVVM, but things a really mixed in my head. Could you please guide me to the simple way how it's possible to 'refresh'/deselect all items once focus is lost on listview?
Thank you.

Answer 1

Here's a quick and dirty example using bindlings. You'll probably have to adjust some it for your needs:
The XAML
<Grid>
<ListBox Name="customerList1"
ItemsSource="{Binding List1Customers}"
SelectedItem="{Binding List1SelectedCustomer, Mode=TwoWay}"/>
<ListBox Name="customerList2"
ItemsSource="{Binding List2Customers}"
SelectedItem="{Binding List2SelectedCustomer, Mode=TwoWay}"/>
</Grid>
The ViewModel
public class Customer
{
public int id { get; set; }
}
public class MyViewModel
{
// This is the collection the first list gets its data from
private ObservableCollection<Customer> list1Customers;
public ObservableCollection<Customer> List1Customers
{
get { return list1Customers; }
set
{
if (list1Customers != value)
{
list1Customers = value;
}
}
}
// This is the customer selected in the first list
private Customer list1SelectedCustomer;
public Customer List1SelectedCustomer
{
get { return list1SelectedCustomer; }
set
{
if (list1SelectedCustomer != value)
{
list1SelectedCustomer = value;
}
}
}
// This is the collection the second list gets its data from
private ObservableCollection<Customer> list2Customers;
public ObservableCollection<Customer> List2Customers
{
get { return list2Customers; }
set
{
if (list2Customers != value)
{
list2Customers = value;
}
}
}
// This is the customer selected in the second list
private Customer list2SelectedCustomer;
public Customer List2SelectedCustomer
{
get { return list2SelectedCustomer; }
set
{
if (list2SelectedCustomer != value)
{
list2SelectedCustomer = value;
}
}
}
public void MoveCustomer(int id)
{
// Find the customer from list 1
var customerToMove = List1Customers.Where(x => x.id == id).FirstOrDefault();
// If it was found...
if (customerToMove != null)
{
// Make the first customer null, which un selects it in the list
List1SelectedCustomer = null;
// Remove the customer from list 1, or comment out if you dont want it removed
List1Customers.Remove(customerToMove);
// Add the customer to list 2
List2Customers.Add(customerToMove);
// Make the newly addec customer in list 2 selected
List2SelectedCustomer = List2Customers.Where(x => x.id == id).FirstOrDefault();
}
}
}