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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
Delpin Susai Raj
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user3871197
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1 Answers1

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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

Adrián Romero
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