Question

我有一个返回列表的类

class Book
{
    public string Title { get; set; }
    public string Author { get; set; }
    public string Year { get; set; }

    public static List<Book> GetList()
    {
        var bookList = new List<Book>();
        bookList.Add(new Book
        {
            Author = "Robin Cook",
            Title = "Vector",
            Year = "1999"

        });
        bookList.Add(new Book
        {
            Author = "J.K. Rowling",
            Title = "Harry Potter and Prisoner of Azkaban",
            Year = "1999"
        });
        bookList.Add(new Book
        {
            Author = "George R.R. Martin",
            Title = "A Dance with Dragons",
            Year = "2011"
        });

        return bookList;
    }
}

我希望该页面包含一个列表视图，每个单元格包含三元组作者 - 标题 - 年份，即

 Robin Cook - Vector - 1999
 ...

在XAML代码中，我有

 var listView = new ListView();
 listView.ItemsSource = Book.GetList();

 var cellTemplate = new DataTemplate(() =>
 {
      var textCell = new TextCell();
      var titleLabel = new Label();
      var authorLabel = new Label();
      var yearLabel = new Label();

      titleLabel.SetBinding(Label.TextProperty, "Title");
      authorLabel.SetBinding(Label.TextProperty, "Author");
      yearLabel.SetBinding(Label.TextProperty, "Year");
      textCell.Text = titleLabel.Text + " - " + authorLabel.Text + " - " + yearLabel;

  return textCell;
 });

 listView.ItemTemplate = cellTemplate;
 Content = listView;

我看到的只是带有连字符的空单元格。你能告诉我我错过了什么吗？

Answer 1

在模型中创建只读属性

public string DisplayText {
  get {
    return $"{Title} - {Author} - {Year}";
  }
}

并绑定到它

var cellTemplate = new DataTemplate(() =>
 {
      var textCell = new TextCell();
      textCell.SetBinding(TextCell.TextProperty, "DisplayText")

  return textCell;
 });

或者，您可以为要显示的每个值创建一个包含三个单独标签的ViewCell

var cellTemplate = new DataTemplate(() => 
{
  var viewCell = new ViewCell();
  var titleLabel = new Label();
  var authorLabel = new Label();
  var yearLabel = new Label();

  titleLabel.SetBinding(Label.TextProperty, "Title");
  authorLabel.SetBinding(Label.TextProperty, "Author");
  yearLabel.SetBinding(Label.TextProperty, "Year");

  StackLayout stack = new StackLayout();
  stack.Children.Add(titleLabel);
  stack.Children.Add(authorLabel);
  stack.Children.Add(yearLabel);

  viewCell.Content = stack;

  return viewCell;
});

Answer 2

在我看来，xaml组件和Book类之间应该存在一些绑定上下文。

如果您想以实施方式实施，可以执行以下操作：

var cellTemplate = new DataTemplate(()=>
{
   var textCell = new TextCell();
            if(i<Book.GetList().Count)
            {
                var titleLabel = new Label();
                var authorLabel = new Label();
                var yearLabel = new Label();

                titleLabel.SetBinding(Label.TextProperty, "Title");
                titleLabel.BindingContext = new { Title = Book.GetList()[i].Title };
                authorLabel.SetBinding(Label.TextProperty, "Author");
                authorLabel.BindingContext = new { Author = Book.GetList()[i].Author };
                yearLabel.SetBinding(Label.TextProperty, "Year");
                yearLabel.BindingContext = new { Year = Book.GetList()[i].Year };
                textCell.Text = titleLabel.Text + " - " + authorLabel.Text + " - " + yearLabel;
                i++;
            }

            return textCell;
}

在Listview中显示具有多个属性的对象

2 个答案: