Xamarin，ListView，如何确定ListView何时滚动到中间？

我想在ListView滚动到中间时调用一个方法

我有列表视图

<ListView x:Name="myListView">
...
</ListView>

myListView.Scrolled侦听器：

public void ScrolledListener(object sender, ScrolledEventArgs args)
{
...
var scrollView = (ListView)sender;
bool isNeededMoreParticipants =
 args.ScrollY >
 (int)(scrollView.Height - scrollView.Height / 2); //Height - is not what I expected. I need the maximum size of ScrollY
...
}

---

如何确定ListView何时滚动到中间？

您似乎想要获取ListView的内容大小。您可以预先设置

ViewCell

或

RowHeight

的高度（设置为静态值或使用数据绑定），如

public void ScrolledListener(object sender, ScrolledEventArgs args)
{
...
var scrollView = (ListView)sender;
bool isNeededMoreParticipants =
 args.ScrollY >
 (int)(scrollView.Height - scrollView.Height / 2); //Height - is not what I expected. I need the maximum size of ScrollY
...
}

<ListView x:Name="MyListView" Scrolled="ListView_Scrolled" ItemsSource="{Binding MyItems}" RowHeight="60">

<DataTemplate>

   <ViewCell>

      <StackLayout HeightRequest="{Binding xxx}">



      </StackLayout>

   </ViewCell>

</DataTemplate>

private void ListView_Scrolled(object sender, ScrolledEventArgs e)
{
   var rowHeight = MyListView.RowHeight;  // you need to set it in xaml in advance , otherwise it will always -1 .If you bind the height in code behind , use the height instead of it

   double contentHeight = rowHeight * MyItems.Count;  // content height of listview

   double positionY = e.ScrollY;

   // if(...) handle your logic 
}