protected override void OnDetachingFrom(MainPage bindable)
 {
     this.viewModel.Messages.CollectionChanged -= Messages_CollectionChanged;
     this.sfChat    = null;
     this.viewModel = null;
     base.OnDetachingFrom(bindable);
 }
        protected override void OnAttachedTo(MainPage bindable)
        {
            this.sfChat    = bindable.FindByName <SfChat>("sfChat");
            this.viewModel = bindable.FindByName <GettingStattedViewModel>("viewModel");
            this.viewModel.Messages.CollectionChanged += Messages_CollectionChanged;

            base.OnAttachedTo(bindable);
        }