c# - 在代码隐藏中绑定(bind)到嵌套对象中的属性

Question

嵌套的 ViewModel 设置为 MainWindow DataContext:

var mainWindow = new MainWindow();
mainWindow.Show();
mainWindow.DataContext = new
{
    MyProperty = new
    {
        MySubProperty = "Hello"
    }
}

在 XAML 中很容易绑定(bind)到 MySubProperty:

<Button Content="{Binding MyProperty.MySubProperty}"/>

如何在代码隐藏中执行此绑定(bind)？

// MyButton.xaml.cs
public partial class MyButton : Button
{
    public MyButton()
    {
        InitializeComponent();
        // todo: add binding here
    }

    // I want this method called if this datacontext is set.
    // and called if MySubProperty changes and INotifyPropertyChange is implemented in the Datacontext.
    public void MySubPropertyChanged(string newValue)
    {
        // ...
    }
}

我无权访问 MyButton.xaml.cs 中的 MainWindow，因此无法将其用作源。

Button 只是一个示例，但这将是一个开始。在我原来的场景中，我没有有用的依赖属性。如果此类绑定(bind)需要 dp，那么包含创建 dp 的示例将非常有帮助。

Answer 1

这个怎么样？ (只是一个肮脏的例子，未经测试，原则上应该可以工作)

// MyButton.xaml.cs
public partial class MyButton : Button
{
    public MyButton()
    {
        InitializeComponent();
        this.DataContextChanged += DataContext_Changed;
    }

    private void DataContext_Changed(Object sender,DependencyPropertyChangedEventArgs e)
    {
       INotifyPropertyChanged notify = e.NewValue as INotifyPropertyChanged;
       if(null != notify)
       {
          notify.PropertyChanged += DataContext_PropertyChanged;
       }
    }

    private void DataContext_PropertyChanged(Object sender,PropertyChangedEventArgs e)   
    {
        if(e.PropertyName == "MySubProperty")
           MySubPropertyChanged((sender as YourClass).MySubProperty);
    } 

    public void MySubPropertyChanged(string newValue)
    {
        // ...
    }
}

编辑:

为了在代码隐藏中绑定(bind)一些东西，你可以使用:

Binding binding = new Binding();
// directly to myproperty
binding.Source = MyProperty;
binding.Path = new PropertyPath("MySubProperty");
// or window
binding.Source = mainWindow; // instance
binding.Path = new PropertyPath("MyProperty.MySubProperty");

// then wire it up with (button is your MyButton instance)
button.SetBinding(MyButton.MyStorageProperty, binding);
//or
BindingOperations.SetBinding(button, MyButton.MyStorageProperty, binding);