Xamarin.Forms ScrollView.ScrollToAsync inside DataTemplate

Question

I have ScrollView inside of a DataTemplate of a ListView. I have a need to horizontally auto scroll the scrollview for each item (to a different point determined by a value inside of my ViewModel which the ListItemViews are bound to).

To my knowledge there's no way to bind the scroll position. How can I call the ScrollView.ScrollToAsync method on the ScrollView inside the DataTemplate?

Thanks!

Jack Hua Jack Hua · Accepted Answer · 2020-02-21T03:11:55

You can try to create a bindableProperty of ScrollView and bind your scroll value to this property, call the ScrollToAsync method in propertyChanged event:

public class CustomScrollView : ScrollView
{
    public static readonly BindableProperty offSetProperty = BindableProperty.Create(
        propertyName: nameof(offSet),
        returnType: typeof(int),
        declaringType: typeof(CustomScrollView),
        defaultValue: 0,
        defaultBindingMode: BindingMode.TwoWay,
        propertyChanged: ScrollOffsetChanged
    );

    static void ScrollOffsetChanged(BindableObject bindable, object oldValue, object newValue)
    {
        var view = (CustomScrollView)bindable;//here you should check if the bindable is CustomScrollView, I don't see your xaml
        view.offSet = (int)newValue;
        view.ScrollToAsync(view.offSet, 0, true);
    }

    public int offSet
    {
        get { return (int)GetValue(offSetProperty); }
        set { SetValue(offSetProperty, value); }
    }
}

Xamarin.Forms ScrollView.ScrollToAsync inside DataTemplate

1 Answers