c# - 通过代码选择 TextCell 不会突出显示行

Question

当我单击 ListView 中的 TextCell 时，该行会突出显示。

但是，当我以编程方式选择一行/一个 TextCell 时，该行未突出显示。

因此，除非用户通过点击一行来更改选择，否则无法向用户指示当前选择了 ListView 中的哪个值。

这是错误还是缺少功能，或者我如何通过代码实现突出显示？

示例代码附在下面。

using MyApp.Model;
using System.Collections.Generic;
using Xamarin.Forms;

namespace MyApp
{
    public class IntSelector : ContentPage
    {
        private ListView m_ListView;

        public IntSelector(int uSelectedInt)
        {
            DataTemplate nTemplate = new DataTemplate(typeof(TextCell));

            // We can set data bindings to our supplied objects.
            nTemplate.SetBinding(TextCell.TextProperty, "String");
            nTemplate.SetBinding(TextCell.DetailProperty, "Int");

            List<clsStringInt> nList = new List<clsStringInt>();

            clsStringInt nItem1 = new clsStringInt { String = "German", Int = 1031 };
            clsStringInt nItem2 = new clsStringInt { String = "English", Int = 1033 };
            clsStringInt nItem3 = new clsStringInt { String = "Spanish", Int = 1034 };

            nList.Add(nItem1);
            nList.Add(nItem2);
            nList.Add(nItem3);

            m_ListView = new ListView();
            m_ListView.ItemTemplate = nTemplate;
            m_ListView.ItemsSource = nList;

            m_ListView.ItemSelected += this.OnSelection;

            m_ListView.SelectedItem = nItem2;//this triggers the "OnSelection" event, so it works
            nItem2.String = "->> " + nItem2.String; //the item's new string is display in the ListView, so that works as well
            //what DOESN'T work is the highliting

            this.Content = m_ListView;
        }

        void OnSelection(object sender, SelectedItemChangedEventArgs e)
        {
            if (e.SelectedItem == null)
            {
                return; //ItemSelected is called on deselection, which results in SelectedItem being set to null
            }

            clsStringInt n = (clsStringInt)e.SelectedItem;
            string sSelectedIntAsString = n.Int.ToString();

            DisplayAlert("Item Selected", sSelectedIntAsString, "Ok");
        }

    }
}

namespace MyApp.Model
{
    public class clsStringInt
    {
        public string String { get; set; }
        public int Int { get; set; }
    }
}

Answer 1

正如您在 UWP Forms 应用程序上测试的评论中提到的，这似乎是该平台上的一个错误，看看它在 Android 和 iOS 上如何正常工作。

我能够通过在 OnAppearing 而不是在 Page 构造函数中设置所选项目来使其突出显示来解决此问题。