Question

I think I need to bind data programmatically to solve my problem.

I use a TabHost which hosts 2 Tabs.
I need to load the MvxBindableListView in the second tab when TabHost appears and keep the first tab as default tab.

What I’m doing is starting the second tab activity without problem because I check the process using this code:

protected override void OnViewModelSet()
    {
        SetContentView(Resource.Layout.Page_ActivityView);
        System.Diagnostics.Debug.WriteLine("activityView started");

        MvxBindableListView mvxBindableListView = FindViewById<MvxBindableListView>(Resource.Id.mvxBindableListView);
        mvxBindableListView.ChildViewAdded += new System.EventHandler<Android.Views.ViewGroup.ChildViewAddedEventArgs>(mvxBindableListView_ChildViewAdded);
    }

“activityView started” is displayed in output debugger, but MvxBindableListView.ChildViewAdded event isn’t raised, only when I click the second tab.

So I suppose that MvxBindableListView is not databound.

Thanks in advance to help me loading my second tab programmatically.

Answer 1

I think ChildViewAdded is an event that occurs when the ListView is rendered – at that time when it needs to ‘draw list items’, then it will ask its adapter for child Views for the screen. As you scroll down the list, it will then ask for more child views – but it will also reuse views – so for a simple list you should only ever (hopefully) get N+1 calls on ChildViewAdded for a list which shows N items at one time.

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So it’s perfectly possible for a list to be databound but never to call ChildViewAdded – that won’t get called until the list is ‘drawn’

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Sadly the Xamarin docs aren’t helpful here – http://docs.mono-android.net/monodoc.ashx?link=E%3AAndroid.Views.ViewGroup.ChildViewAdded

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Note: if you do actually want to bind programatically, then you can do this to – using Bind() methods and extension methods. However, I haven’t expanded on that here – as it doesn’t sound like that’s actually what you need!