Automatically scroll down ListView in Xamarin-CodePudding

I have ListView with binding ItemsSource (it is ObservableRangeCollection). I want to automatically scroll down ListView when page is appearing. What should I do?
It is View:

<ListView 
        x:Name="ListAdd"            
        ItemsSource="{Binding AddNewFlashcard}"
        (...)
            >
            <ListView.Behaviors>
                <(...)>
            </ListView.Behaviors>
            <ListView.ItemTemplate>
                <DataTemplate x:DataType="models:Flashcard">
                    <ViewCell>
                        <Grid Padding="10">
                            <Frame CornerRadius="20" HasShadow="True">
                                <StackLayout VerticalOptions="Center">
                                    <Label FontSize="Large"
                                        Text="{Binding Word}"
                                   VerticalOptions="Center"/>
                                    <Label Text="{Binding Sentence}"
                                   VerticalOptions="Center"/>
                                </StackLayout>
                            </Frame>
                        </Grid>
                    </ViewCell>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>

It is ViewModel:

public ObservableRangeCollection<Flashcard> AddNewFlashcard { get; set; }

        public NewFlashcardVM()
        {            
            Refresh();
            AddNewFlashcard = new ObservableRangeCollection<Flashcard>(); 
        }



        public async void Refresh() 
        {
            IsBusy = true;      
            var flashcards = await FlashcardService.GetFlashcard();
            AddNewFlashcard.AddRange(flashcards);
            IsBusy = false;
        }

CodePudding user response：

You can achieve the effect you want by calling the ScrollTo method in the ListView.

I wrote a small example for your reference.

Here is the xaml code:

<StackLayout>
    <Frame HeightRequest="100">
        <ListView x:Name="mytest" >
            <ListView.ItemTemplate>
                <DataTemplate>
                    <ViewCell>
                        <Label Text="{Binding .}"></Label>
                    </ViewCell>
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
    </Frame>
</StackLayout>

Here is the background code(When the data is loaded, call the ScrollTo method of ListView in the OnAppearing method):

public partial class MainPage : ContentPage
{
    ObservableRangeCollection<string> myList;
    public MainPage()
    {
        InitializeComponent();
        myList = new ObservableRangeCollection<string>();
        myList.Add("aaa");
        myList.Add("aaa");
        myList.Add("aaa");
        myList.Add("aaa");
        myList.Add("aaa");
        myList.Add("aaa"); 
        myList.Add("bbb");
        mytest.ItemsSource = myList;
        BindingContext = this;
    }
    protected override void OnAppearing()
    {
        base.OnAppearing();
        mytest.ScrollTo(myList[myList.Count-1], ScrollToPosition.End,false);
    }
}

If you change the last parameter of ScrollTo to true, a sliding animation will occur.