MessengCenter too Slow

Question

Hello

When I tried to select a notebook in my notebook app, I Was using this code

public Notebook RecivedSelectedNotebook { get; set; }

         public Note SeletedNote { get; set; }

         public NotesPageViewModel() {

             FabAnimationCommmand = new Command<Frame>(AnimateButtonCommand);

             RecivedSelectedNotebookAccion = (SelectedObject) => {

                 RecivedSelectedNotebook = SelectedObject;
             }; // here I put a breakpoint and I get the RecivedSelectedNotebook object

             Services.ReadAsync(App.Notes, RecivedSelectedNotebook.Id); // here for  some reason RecivedSelectedNotebook is null
         }

Because It was null I change it and used the xamarin messaging center

public NotesPageViewModel() {

        Services = App.services;

        FabAnimationCommmand = new Command<Frame>(AnimateButtonCommand);

        MessagingCenter.Subscribe<MainPageViewModel, Notebook>(this, App.NotebookID, (sender, value) => {
            RecivedSelectedNotebook = value;
            Services.ReadAsync(App.Notes, RecivedSelectedNotebook.Id);

            MessagingCenter.Unsubscribe<MainPageViewModel, Notebook>(this, App.NotebookID);
        });

Now the problem is this

Video error: https://reccloud.com/u/mh5izje

project: https://github.com/eduardoagr/DuoNotes

Answer 1

To improve the performance, try to move to the MessagingCenter.Send before navigation.

public async virtual void SeletedItemActionAsync()
{
    if (SelectedNotebook == null)
    {
        return;
    }
    //MessagingCenter.Send();
    await Application.Current.MainPage.Navigation.PushAsync(notesPage);
    SelectedNotebook = null;
}

If it stil doesn't work, try to store the data and then retrive the data in the

public async virtual void SeletedItemActionAsync()
{
    if (SelectedNotebook == null)
    {
        return;
    }
    Application.Current.Properties["id"] = App.NotebookID;//if the id is global static, you could use it directly
    Application.Current.Properties["selected_object"] = SelectedNotebook;
    await Application.Current.MainPage.Navigation.PushAsync(notesPage);
    SelectedNotebook = null;
}

public NotesPageViewModel()
{

    Services = App.services;

    FabAnimationCommmand = new Command<Frame>(AnimateButtonCommand);

    if (Application.Current.Properties.ContainsKey("id"))
    {
        var selectedObject = Application.Current.Properties["selected_object"] as Notebook;
    }
    ...
}

Answer 2

Hi, EduardoGomez-1870. To pass the info, you could create a parameterized constructor method for 'NotesPage'. Then pass the notebook id and the selected object when navigating to the 'NotesPage' as below.

NotesPage notesPage = new NotesPage(App.NotebookID, SelectedNotebook);
await App.Current.MainPage.Navigation.PushAsync(notesPage);