Problem of Xamarin.Form (ListView not refresh if binding from Akavache cache)

Question

I met a problem with refresh list.

I'm using MasterDetailPage with init default in Visual Studio 2019 (Xamarin.Forms 4.3.0.991250) & Akavache 6.6.1, has a variable is Items of type ObservableCollection<TodoItem>.

The first, i added one item to cache (i call this object is TodoItem). And then show ListView with Items binding got from Akavache cache, but it's not working, Items has values -> ListView not refresh.

I tried with something:

• Change version (Xamarin.Forms & Akavache), Ex: XF 4.1 highest version and akavache downgrade 6.0, 6.1, 6.2... => not working.

• If setup Items with hardcode new ObservableCollection(new ListView(){ ... }) => it's working.

• If app running, i change something on the layout and save (Xaml hot reload) -> it's working.

  public ObservableCollection Items { get; set; } = new ObservableCollection();

  #region AddNewCommand
  
  private Command _addNewCommand;
  
  public Command AddNewCommand =>
      _addNewCommand ?? (_addNewCommand = new Command(async (p) => await AddNewExecute(), (p) => !IsBusy));
  
  private async Task AddNewExecute()
  {
      var key = Guid.NewGuid().ToString().Substring(0, 5);
      await BlobCache.LocalMachine.InsertObject<TodoItem>(key, new TodoItem() {Id=key.Substring(0,2),Text="abc",Description="def" }, new TimeSpan(1, 0, 0));
      var list = await BlobCache.LocalMachine.GetAllObjects<TodoItem>();
      Items = new ObservableCollection<TodoItem>(list);
  }
  #endregion
  

Answer 1

In order to make a change to a variable bindend to the UI you have to do it inside BeginInvokeOnMainThread

Something like this:

private async Task AddNewExecute()
{
     var key = Guid.NewGuid().ToString().Substring(0, 5);
     await BlobCache.LocalMachine.InsertObject<TodoItem>(key, new TodoItem() 
        {
          Id=key.Substring(0,2),Text="abc",Description="def" }, new TimeSpan(1, 0, 0));
          Device.BeginInvokeOnMainThread (async () => {
          var list = await BlobCache.LocalMachine.GetAllObjects<TodoItem>();
          Items = new ObservableCollection<TodoItem>(list);
        });
}

In this way you're changing the variable on the UI thread