Question

我有一个具有HasUnevenRows = true的ListView。

我将ItemSource绑定到ObservableCollection。

此Collection用一些行填充ListViews。每行都有不同的高度，因为行与行之间的文本是不同的。

我想知道是否可以知道每一行的高度。

谢谢亚历山德罗

            IEnumerable<PropertyInfo> pInfos = (ListViewPrivacy as ItemsView<Cell>).GetType().GetRuntimeProperties();
            var templatedItems = pInfos.FirstOrDefault(info => info.Name == "TemplatedItems");
            if (templatedItems != null)
            {
                var cells = templatedItems.GetValue(ListViewPrivacy);
                foreach (ViewCell cell in cells as Xamarin.Forms.ITemplatedItemsList<Xamarin.Forms.Cell>)
                {

                    if (cell.BindingContext != null)
                    {

                        System.Diagnostics.Debug.WriteLine("CellHeight = " + cell.Height + " - " + cell.RenderHeight + " " + cell.View.Height + " - " + cell.View.HeightRequest + " - " + cell.View.MinimumHeightRequest + " - " );
                        Grid grid = (Grid)cell.View;
                        System.Diagnostics.Debug.WriteLine("Height = " +  grid.Height.ToString() + " - " + grid.HeightRequest + " - " + grid.MinimumHeightRequest);


                    }
                }
            }

我尝试过使用这样的代码，但每个属性中的值始终为“ -1”

Answer 1

好的，我找到了解决方案。

            <ViewCell>
                <Grid
                    SizeChanged="ViewCell_SizeChanged"

这是ViewCell_SizeChanged：

    double totalHeight = 0;
    int counter = 0;

    private void ViewCell_SizeChanged(object sender, EventArgs e)
    {

        if(sender is Grid)
        {
            Grid grid = (Grid)sender;

            totalHeight += grid.Height;
            totalHeight += grid.Margin.Top;
            totalHeight += grid.Margin.Bottom;

            if(++counter == ((MyViewModel)this.BindingContext).MyObservableCollection.Count)
                Device.BeginInvokeOnMainThread(() => MyListView.HeightRequest = totalHeight);
        }
    }

当ViewCell充满数据时，将调整网格的大小，以便引发ViewCell_SizeChanged事件。在这里，我有当前的Grid.Height和Margin值。当我达到项目总数时，我在ListView中具有所有网格的确切高度

Answer 2

我想根据 Alessandro 的回答分享我的解决方案，但使用 FlowListView。我需要设置FlowListView HeightRequest，因为列表后面有一个巨大的空白空间。

XAML

<flv:FlowListView
     FlowColumnCount="1"
     FlowItemsSource="{Binding Coverages}"
     SeparatorVisibility="None"
     VerticalScrollBarVisibility="Never"
     x:Name="listConverages"
     HasUnevenRows="True">
     <flv:FlowListView.FlowColumnTemplate>
         <DataTemplate>
             <StackLayout
                  SizeChanged="StackLayout_SizeChanged">
             </StackLayout>
         </DataTemplate>
     </flv:FlowListView.FlowColumnTemplate>
</flv:FlowListView>

背后的代码

private Dictionary<Guid, double> itemsHeight = new Dictionary<Guid, double>();
private void StackLayout_SizeChanged(object sender, EventArgs e)
{
    StackLayout stackLayout = (StackLayout)sender;

    if (!itemsHeight.ContainsKey(stackLayout.Id))
        itemsHeight.Add(stackLayout.Id, stackLayout.Height);
    else
        itemsHeight[stackLayout.Id] = stackLayout.Height;

    listConverages.HeightRequest = itemsHeight.Sum(x => x.Value);
}

注意：如果您有下边距或上边距，请在将项目添加到字典之前将它们添加到值中

Xamarin.Forms ListView。我能知道每一行的高度吗？

2 个答案: