Question

I have a parent window which has a ListView that is bound to an ObservableCollection that gets it’s data from an XML file. On the parent window, I have an add button that opens a opens a Modal Window (form2.ShowDialog(), I think this is a Modal window).

In the child window I have a few text fields and an add button, the user enters data for a new record and clicks the Add button and the XML file is updated with the new record.

What I am seeking to do is when the child window is closed that the ListView in the parent window is refreshed to show the new record.

When I am updating the XML file from the child window, I am doing this directly to the XML file, should I be adding the data to the file in some other manner which would raise an event on the ObservableCollection?

I was heading down the path of adding an event handler to the add button on the parent window and attempt to force a re-read of the XML file, but I cannot figure out how to achieve this, below is what I have done so far.

form1.xaml.vb:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles Button1.Click
        Dim frm As New newEmergencyContact
        AddHandler frm.Closed, AddressOf refresh_EmContacts
        frm.ShowDialog()
    End Sub
    Private Sub refresh_EmContacts()

    End Sub

I cannot workout what should go into the refresh_EmContacts sub, do I need to call some kind of ObservableCollection event handler to notify it that it has been updated and to do the re-read?

Any assistance would be greatly appreciated.

Matt

Answer 1

You might be better off updating the ObservableCollection directly with the new item, and then if you wish to persist the change to the XML file at that point, you could subscribe to the ObservableCollection’s CollectionChanged event and you can inspect the event args passed to your handler to get information about the item added.