c# - 绑定(bind)到 XAML 中的用户控件集合

Question

我有一组要在堆栈面板中显示的用户控件。我无法控制这些用户控件包含的方式和内容。我只知道它们是某种用户控件(可以是按钮、文本 block 或任何 UIElement。)这是一个小例子

public class Car : IHasView
{
     public UserControl MyView { get return new MyCarViewThatHasAButton(); }
}

public class Jeep : IHasView
{
    public UserControl MyView { get return new MyJeepViewThatHasATextblock(); }
}

public class MainView : INotifyPropertyChanged{
    private ICollection _myViews;
    public ICollection MyViews {
    get { return _myViews;}
    set{ 
       _myViews = value; 
       NotifyPropertyChanged("MyViews");
    }

...
...
}

在此示例中，我想绑定(bind)到 MyViews 并在堆栈面板中显示集合中的所有 View 。我应该怎么去绑定(bind)它？我是 WPF 世界的新手。

谢谢。

Answer 1

这是一个实现方法的示例。

如果您只想要默认的 ItemsPanel 模板(垂直堆栈面板)，则可以删除 ItemsControl 的 ItemsControl.ItemsPanel 部分 - 我只是多余地包含它，以便您可以看到 StackPanel 实际存在的位置，或者如果您想要以某种方式更改 StackPanel。

ItemTemplate 由 HasViewItemTemplate 的键名显式引用，因为您不能隐式应用数据模板，因为您的数据项是接口(interface)类型。

[您可能需要做更多工作，例如在 MyCarViewThatHasAButton 和 MyCarViewThatHasAButton 上使用单例，为 NotifyPropertyChanged 使用更好的模式等。]

---

<Window x:Class="WpfApplication3.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:WpfApplication3="clr-namespace:WpfApplication3" Title="MainWindow" Height="350" Width="525">
    <Window.Resources>
        <WpfApplication3:MainView x:Key="MainView"/>
        <DataTemplate x:Key="HasViewItemTemplate">
            <ContentPresenter Content="{Binding Path=MyView}"/>
        </DataTemplate>
    </Window.Resources>
    <Grid>
        <ItemsControl Background="Yellow" ItemTemplate="{StaticResource HasViewItemTemplate}" ItemsSource="{Binding Source={StaticResource MainView}, Path=MyViews}">
            <ItemsControl.ItemsPanel>
                <ItemsPanelTemplate>
                    <VirtualizingStackPanel Orientation="Vertical"/>
                </ItemsPanelTemplate>
            </ItemsControl.ItemsPanel>
        </ItemsControl>
    </Grid>
</Window>



using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Collections;
using System.ComponentModel;
using System.Collections.ObjectModel;

namespace WpfApplication3
{
    public interface IHasView
    {
        UserControl MyView { get; }
    }

    public class Car : IHasView
    {
        public UserControl MyView
        { 
            get
            {
                // Demo UserControl as prodcued by MyCarViewThatHasAButton

                UserControl ctl = new UserControl();

                ctl.Background = Brushes.Red;

                Button button = new Button();

                button.Content = "a car";

                ctl.Content = button;

                return ctl;
            }
        }
    }

    public class Jeep : IHasView
    {
        public UserControl MyView
        {
            get
            {
                // Demo UserControl as produced by MyJeepViewThatHasATextblock

                UserControl ctl = new UserControl();

                ctl.Background = Brushes.Blue;
                ctl.Width = 50;

                TextBlock textblock = new TextBlock();

                textblock.Text = "a jeep";

                ctl.Content = textblock;

                return ctl;
            }
        }
    }

    public class MainView : INotifyPropertyChanged{

        public MainView()
        {
            ObservableCollection<IHasView> list = new ObservableCollection<IHasView>()
                                                      {
                                                          new Car(),
                                                          new Jeep()
                                                      };

            MyViews = list;
        }

        private ICollection _myViews;
        public ICollection MyViews
        {
            get
            {
                return _myViews;
            }
            set
            { 
               _myViews = value; 
               NotifyPropertyChanged("MyViews");
            }
        }

        private void NotifyPropertyChanged(string p)
        {
            if (PropertyChanged != null)
            {
                PropertyChangedEventArgs e = new PropertyChangedEventArgs(p);

                PropertyChanged(this, e);
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;
    }

    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
        }
    }
}