c# - Xamarin Forms ListView 不显示 TextCells

Question

这是我现在正在使用的代码...

items = new List<TextCell>();
        items.Add(new TextCell { Text = "Cake", TextColor = Color.Green, Detail = "12 hours left!", DetailColor = Color.Black});
        items.Add(new TextCell { Text = "Pie", TextColor = Color.Green, Detail = "14 hours left!", DetailColor = Color.Black });


        var buy = new ContentPage
        {
            Title = "Buy",
            Content = new StackLayout
            {
                VerticalOptions = LayoutOptions.Center,
                Children = {
                    new ListView
                    {
                       ItemsSource = items,
                       ItemTemplate = new DataTemplate(typeof(TextCell))
                    }
                }
            }
        };

ListView 填充了两个没有内容的空白 View 。

我是否缺少某些属性？

Answer 1

对于 ListView，ItemsSource 是包含数据的对象集合，但它们本身不是 Views/Cells/其他 UI 对象。它们是您的域数据。

另一方面，ItemTemplate 需要返回一个设置了正确绑定(bind)的 Cell，因此当 ListView 将其 BindingContext 设置为来自 ItemsSource 的对象时，所有字段都已设置。

对于您的情况，它可能看起来像:

public class ThingToBuy
{
    public string What { get; set; }
    public string HowLong { get; set; }
}

items = new List<ThingToBuy>();
items.Add(new ThingToBuy { What = "Cake", HowLong = "12 hours left!" });
items.Add(new ThingToBuy { What = "Pie", HowLong = "14 hours left!" });

        var buy = new ContentPage
        {
            Title = "Buy",
            Content = new StackLayout
            {
                VerticalOptions = LayoutOptions.Center,
                Children = {
                    new ListView
                    {
                       ItemsSource = items,
                       ItemTemplate = new DataTemplate(() => {
                           var cell = new TextCell();
                           cell.SetBinding(Label.TextProperty, "What");
                           cell.SetBinding(Label.DetailProperty, "HowLong");
                           return cell;
                       })
                    }
                }
            }
        };

有关 ItemsSource/ItemTemplate 的更多详细示例，请参阅 ListView 的文档:https://developer.xamarin.com/api/type/Xamarin.Forms.ListView/