WPF绑定列表框主/ [英] WPF Binding ListBox Master/Detail

问题描述

我能得到这个工作与将XmlDataSource，但不符合我自己的类。所有我想要做的是列表框绑定到我的收藏实例，然后将文本框链接到列表框这样我就可以编辑人的姓名（双向）。我刻意保持这种尽可能简单，希望有人可以填空。

I can get this working with an XmlDataSource but not with my own classes. All I want to do is bind the listbox to my collection instance and then link the textbox to the listbox so I can edit the person's name (two-way). I've deliberately kept this as simple as possible in the hope that somebody can fill in the blanks.

XAML：

<Window x:Class="WpfListTest.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:WpfListTest"
    Title="Window1" Height="300" Width="600">
    <Grid>
        <Grid.ColumnDefinitions>
            <ColumnDefinition Width="160"/>
            <ColumnDefinition Width="3"/>
            <ColumnDefinition Width="1*"/>
        </Grid.ColumnDefinitions>
        <DockPanel Grid.Column="0">
            <ListBox />
        </DockPanel>
        <DockPanel Grid.Column="2">
            <StackPanel>
                <Label>Name</Label>
                <TextBox />
            </StackPanel>
        </DockPanel>
    </Grid>
</Window>

C＃$ C $落后C：

C# code behind:

namespace WpfListTest
{
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window
    {
        public People MyPeeps = new People();

        public Window1()
        {
            InitializeComponent();

            MyPeeps.Add(new Person("Fred"));
            MyPeeps.Add(new Person("Jack"));
            MyPeeps.Add(new Person("Jill"));
        }
    }

    public class Person
    {
        public string Name { get; set; }

        public Person(string newName)
        {
            Name = newName;
        }
    }

    public class People : List<Person>
    {
    }
}

所有网站上的例子似乎有什么实际上是一个静态类返回code定义的数据（如返回新的Person（等等等等）），而不是我自己的一个集合的实例 - 在这种情况下， MyPeeps。或者，也许我不会说出正确的搜索咒语。

All the examples on the web seem to have what is effectively a static class returning code-defined data (like return new Person("blah blah")) rather than my own instance of a collection - in this case MyPeeps. Or maybe I'm not uttering the right search incantation.

有一天我可能会理解这约束力的东西，但目前它莫名其妙我突然突破。任何帮助AP preciated。

One day I might make a sudden breakthrough of understanding this binding stuff but at the moment it's baffling me. Any help appreciated.

推荐答案

正确的方法是使用MVVM模式，并创建一个视图模型，如下所示：

The correct way would be to use the MVVM pattern and create a ViewModel like so:

public class MainWindowViewModel : INotifyPropertyChanged
{
    private People _myPeeps;
    private Person _selectedPerson;

    public event PropertyChangedEventHandler PropertyChanged;

    public People MyPeeps
    {
        get { return _myPeeps; }
        set
        {
            if (_myPeeps == value)
            {
                return;
            }
            _myPeeps = value;
            RaisePropertyChanged("MyPeeps");
        }
    }

    public Person SelectedPerson
    {
        get { return _selectedPerson; }
        set
        {
            if (_selectedPerson == value)
            {
                return;
            }
            _selectedPerson = value;
            RaisePropertyChanged("SelectedPerson");
        }
    }

    private void RaisePropertyChanged(string propertyName)
    {
        var handler = PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(propertyName));
        }
    }
}

初​​始化它在您查看的code后面像这样：

Initialize it in your View's code behind like so:

public partial class MainWindow : Window
{
    private readonly MainWindowViewModel _viewModel;

    public MainWindow()
    {
        _viewModel = new MainWindowViewModel();
        _viewModel.MyPeeps = new People();
        _viewModel.MyPeeps.Add(new Person("Fred"));
        _viewModel.MyPeeps.Add(new Person("Jack"));
        _viewModel.MyPeeps.Add(new Person("Jill"));
        DataContext = _viewModel;

        InitializeComponent();
    }
}

和绑定的数据，像这样：

And bind the data like so:

<Window x:Class="WpfApplication3.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow"
        Height="350"
        Width="525">
  <Grid>
    <Grid.ColumnDefinitions>
      <ColumnDefinition Width="160" />
      <ColumnDefinition Width="3" />
      <ColumnDefinition Width="1*" />
    </Grid.ColumnDefinitions>
    <DockPanel Grid.Column="0">
      <ListBox SelectedItem="{Binding SelectedPerson}"
               DisplayMemberPath="Name"
               ItemsSource="{Binding MyPeeps}" />
    </DockPanel>
    <DockPanel Grid.Column="2">
      <StackPanel>
        <Label>Name</Label>
        <TextBox Text="{Binding SelectedPerson.Name}" />
      </StackPanel>
    </DockPanel>
  </Grid>
</Window>

的结合将工作是这样的：

The binding will work like this:

本身设置为视图模型实例窗口的DataContext的。由于列表框和文本框不指定任何的DataContext ，他们从窗口继承它。在对象上的绑定，如果被指定的没有别的总是工作相对的DataContext 。这意味着文本框的结合会在其的DataContext SelectedPerson $ C>（即在 MainWindowViewModel ）和一个属性在名称 SelectedPerson 。

The DataContext of the window itself is set to the ViewModel instance. Because the ListBox and the TextBox don't specify any DataContext, they inherit it from the Window. The bindings on an object always work relative to the DataContext if nothing else is being specified. That means that the TextBox binding looks for a property SelectedPerson in its DataContext (i.e., in the MainWindowViewModel) and for a Property Name in that SelectedPerson.

是该样品的基本机制如下： 在视图模型的 SelectedPerson 属性始终与的SelectedItem 的列表框同步和文本框的文本属性始终与名称同步的属性 SelectedPerson 。

The basic mechanics of this sample are as follows: The SelectedPerson property on the ViewModel is always synchronized with the SelectedItem of the ListBox and the Text property of the TextBox is always synchronized with the Name property of the SelectedPerson.

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