c# - 字典 - 文本框绑定(bind)不起作用

Question

我没有使用 View 模型，有一个类似的帖子使用了 View 模型，我试图以此为基础，但它不起作用，
WPF binding textbox to dictionary entry

当我单击我的按钮时，我创建了一个列表，然后形成了一个字典，因此在我精简的示例中以使其工作，我在按钮单击时创建字典

代码隐藏

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        this.DataContext = this;
    }
private Dictionary<string, string> _MyDict;


    public Dictionary<string, string> MyDict        {
        get { return _MyDict; }
        set { _MyDict= value; }
    }
 private void button_Click(object sender, RoutedEventArgs e)
    {
      MyDict = new Dictionary<string, string>
       { 
          {"First", "Test1"},
          {"Second", "Test2"}
       };
    }
  }

XAML

Title="MainWindow" Height="350" Width="674.167">
<Grid>
    <Button x:Name="createListfromTextFile" Content="hi" Click="button_Click"/>

    <TextBox x:Name="textBox1"  Text="{Binding MyDict[First], UpdateSourceTrigger=PropertyChanged}" Height="279" >

</Grid>

更新

根据 Chrille 的评论，我解决了这个问题，
通过实现 INotifyPropertyChanged像这样:

public partial class MainWindow : Window, INotifyPropertyChanged
{
    public MainWindow()
    {
        InitializeComponent();
        this.DataContext = this;
    }

 public Dictionary<string, string> MyDict
    {
        get { return _MyDict; }
        set {

            _MyDict = value;
            if (null != PropertyChanged)
            {
                this.PropertyChanged(this, new PropertyChangedEventArgs  ("MyDict"));
            }
        }          
     }
  }

Answer 1

您的 MainWindow 类 (DataContext) 需要实现 INotifyPropertyChanged。

public partial class MainWindow : Window, INotifyPropertyChanged
{
    public MainWindow()
    {
        InitializeComponent();
        this.DataContext = this;
    }

    public Dictionary<string, string> MyDict
    {
        get { return _MyDict; }
        set 
        {
            _MyDict = value;
            PropertyChanged?.(this, new PropertyChangedEventArgs("MyDict"));
        }         
    }
}

或者更好的是，为 View 模型创建一个单独的类并从 ViewModelBase 或类似继承:

public abstract class ViewModelBase : INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void NotifyPropertyChanged(params string[] propertyName)
        {
            foreach (var prop in propertyName)
            {
                OnPropertyChanged(new PropertyChangedEventArgs(prop));
            }
        }

        protected virtual void OnPropertyChanged(PropertyChangedEventArgs args)
        {
            if (PropertyChanged != null)
            {
                PropertyChanged.Invoke(this, args);
            }
        }
    }

最后在二传手:

public Dictionary<string, string> MyDict
{
    get { return _MyDict; }
    set 
    {
        _MyDict = value;
        NotifyPropertyChanged("MyDict");
    }         
}