在 xamarin c# 中以编程方式绑定列表视图

Question

我想在 Xamarin 便携版中创建一个列表视图， 列表视图的项目来源是List<String>，我的列表视图数据模板是由这个函数准备的，

private DataTemplate createItemtemplate()
{
    try
    {
        Label lbl_binding = new Label()
        {
            TextColor = Color.Red,
            FontSize = 16,
            VerticalTextAlignment = TextAlignment.Center,
            HorizontalOptions = LayoutOptions.CenterAndExpand,
        };
        lbl_binding.SetBinding(Label.TextProperty, ".");
        StackLayout stkBottom = new StackLayout()
        {
            Orientation = StackOrientation.Horizontal,
            HorizontalOptions = LayoutOptions.CenterAndExpand,
            VerticalOptions = LayoutOptions.Center,
            Padding = new Thickness(0),
        };
        stkBottom.Children.Add(lbl_binding);
        ViewCell vc = new ViewCell() {
            View = stkBottom
        };

        DataTemplate Dp = new DataTemplate(() =>
        {
            return vc;
        });
        return Dp;
    }
    catch (Exception ex)
    {
        return null;
    }
}

现在，我的列表视图已填充，但所有标签都填充了最后一项，我的意思是正确填充了项数，但所有项仅填充了最后一项。 我在这里做错了什么？

lstAdmin = new ListView()
{
    ItemTemplate = createItemtemplate(),
};
lstadmin.Itemsource = source;

Answer 1

将您的列表视图从 List 更改为 ObservableCollection。这应该可以完成工作。

Answer 2

下面的代码对你很有参考价值

参加班级成员：

   public class Dummy
    {

    public string Id { get; set; }
    public string Img { get; set; }
    public string Title { get; set; }
    public string SubTitle { get; set; }
    public string Count { get; set; }
    public string Status { get; set; }

    }

创建一个 ObservableCollectionList：

   ObservableCollection<Dummy> productItems = new 
   ObservableCollection<Dummy>();

将项目添加到 ObservableCollectionList：

   productItems.Add(new Dummy() { Name = "0", Img = "Avatar.png", 
   Title = "Total Books", SubTitle = "Desc", Count = "50", Status = 
   "Total" });

   productItems.Add(new Dummy() { Id = "1", Img = "Avatar.png", Title 
   = "Out of Stock Books", SubTitle = "Desc", Count = "40", Status = 
   "OutStock" });

声明 ListView：

   ListView listview = new ListView()
        {
            VerticalOptions = LayoutOptions.FillAndExpand,
            HorizontalOptions = LayoutOptions.FillAndExpand,
            SeparatorVisibility = SeparatorVisibility.None,
            RowHeight = 30,
        };
listview.ItemTemplate = new DataTemplate(typeof(cell));
listview.ItemSelected += listviewItemSelected;

使用 ViewCell 并在 ViewCell 中设计您的 UI 并分配绑定

    public class cell : ViewCell
    {
        public cell()
        {
            Image img = new Image()
            {
                VerticalOptions = LayoutOptions.StartAndExpand,
            };

            img.SetBinding(Image.SourceProperty, new Binding("Img"));

            Label lbltitle = new Label()
            {
                VerticalOptions = LayoutOptions.Start,
                TextColor = Color.Black
            };

            lbltitle.SetBinding(Label.TextProperty, new 
           Binding("Title"));

            Label lbldesc = new Label()
            {
                VerticalOptions = LayoutOptions.Start,
                TextColor = Color.Black
            };

            lbldesc.SetBinding(Label.TextProperty, new 
            Binding("SubTitle"));

            StackLayout lblstack = new StackLayout()
            {
                VerticalOptions = LayoutOptions.FillAndExpand,
                HorizontalOptions = LayoutOptions.FillAndExpand,
                Children = { lbltitle, lbldesc },
            };
            BoxView boxEdit = new BoxView()
            {
                VerticalOptions = LayoutOptions.Start,
                HorizontalOptions = LayoutOptions.End,
                Color = Color.Black,
                HeightRequest = 20,
                WidthRequest = 10
            };

            tapGestureEdit.Tapped += tapGestureEditTapped;
            Label lblCount = new Label()
            {
                VerticalOptions = LayoutOptions.CenterAndExpand,
                HorizontalOptions = LayoutOptions.FillAndExpand,
                TextColor = Color.Black
            };
            lblCount.SetBinding(Label.TextProperty, new 
            Binding("Count"));
            StackLayout stackCount = new StackLayout()
            {
                VerticalOptions = LayoutOptions.FillAndExpand,
                HorizontalOptions = LayoutOptions.EndAndExpand,
                Children = { boxEdit, lblCount },
            };
            StackLayout stackMain = new StackLayout()
            {
                VerticalOptions = LayoutOptions.FillAndExpand,
                HorizontalOptions = LayoutOptions.FillAndExpand,
                Children = { img, lblstack, stackCount },
                Orientation = StackOrientation.Horizontal,
                Margin = new Thickness(10, 10, 10, 10)
            };
            View = stackMain;
        }
     }

Answer 3

public class AdminCell : ViewCell
{
    public AdminCell()
    {
        Label lbl_binding = new Label()
        {
            TextColor = Color.FromRgb(30, 144, 255),
            FontSize = 16,
            VerticalTextAlignment = TextAlignment.Center,
            HorizontalOptions = LayoutOptions.CenterAndExpand,
        };
        lbl_binding.SetBinding(Label.TextProperty, ".");
        StackLayout stkBottom = new StackLayout()
        {
            Orientation = StackOrientation.Horizontal,
            HorizontalOptions = LayoutOptions.CenterAndExpand,
            VerticalOptions = LayoutOptions.Center,
            Padding = new Thickness(0),
        };
        stkBottom.Children.Add(lbl_binding);
        View = stkBottom;
    }
}

此代码为我工作删除了模板并使用此单元格，我仍然不明白为什么数据模板不起作用

Answer 4

我遇到了同样的问题，经过一些测试，我想出了如何不总是得到最后一项。

您应该像这样将标签创建和所有其他要放入 ItemTemplate 的元素放在 DataTemplate 的 lambda 中（示例代码）：

DataTemplate itemTemplate = new DataTemplate(() =>
            {
                Label label = new Label()
                {
                    Margin = new Thickness(45, 0, 0, 0),
                    HorizontalOptions = LayoutOptions.Start,
                    FontSize = (double)Xamarin.Forms.Application.Current.Resources["BodyFontSize"],
                    HeightRequest = 20
                };
                label.SetBinding(Label.TextProperty, "Name");

                ViewCell templateCell = new ViewCell()
                {
                    View = label
                };

                return templateCell;
            });

希望有所帮助（在我的情况下有所帮助）。