为什么在控件值更改后不更新绑定项

我很难绑定属性。我可能遗漏了什么。问题是，直到我与UI进行另一次交互，比如按下一个空的虚拟按钮，我的对象属性才会被界面控件更改更新。这真的很奇怪。我错过了什么?如何使绑定属性在控件检查更改时更新?

示例:

创建一个空表单，添加一个复选框和一个按钮。
• 将复选框绑定到IsOnSale Car属性
• 添加一个控制台写入行来查看何时IsOnSale属性将被更改
• 构建并点击复选框，IsOnSale不会改变(没有控制台消息)，直到点击另一个按钮或其他东西。

• 点击dummy按钮，IsOnSale属性将被更改!什么! ? ?

  private Car car;
  public Form1()
  {
      InitializeComponent();
      car = new Car();
      car.IsOnSale = false;
      checkBox1.DataBindings.Add("Checked", car, "IsOnSale");
  }
  //U dont need this for the test..
  private void btnPrintStatus_Click(object sender, EventArgs e)
  {
      string s = car.ToString();
      Console.WriteLine(s);
  }
  

Car只是一个实现INotifyPropertyChanged的类。此外，每次发出属性更改请求时，它都会在控制台上打印(只是为了调试)。正如您所看到的，如果您构建了示例，那么更改请求只会在单击虚拟按钮之后发出…

internal class Car : INotifyPropertyChanged, INotifyPropertyChanging
{
    private string name;
    public string Name
    {
        get { return name; }
        set
        {
            string propName = GetName(new { Name });
            UpdateField(ref name, value, propName, null);
        }
    }
    private bool isOnSale;
    public bool IsOnSale
    {
        get { return isOnSale; }
        set
        {
            string propName = GetName(new { IsOnSale });
            UpdateField(ref isOnSale, value, propName, null);
        }
    }
    public override string ToString()
    {
        return string.Format("Car Name: {0}. IsOnSale: {1}", Name, IsOnSale);
    }
    #region  INotifyPropertyChanged, INotifyPropertyChanging
    public event PropertyChangingEventHandler PropertyChanging;
    public event PropertyChangedEventHandler PropertyChanged;
    public static string GetName<T>(T item) where T : class
    {
        return typeof(T).GetProperties()[0].Name;
    }
    protected bool UpdateField<T>(ref T field, T newValue, string propertyName, Action action = null)
    {
        bool needChange = !EqualityComparer<T>.Default.Equals(field, newValue);
        Console.WriteLine("Try to UpdateField {0}. Need update? {1}", propertyName, needChange);
        if (needChange)
        {
            OnPropertyChanging(propertyName);
            field = newValue;
            if (action != null)
                action();
            OnPropertyChanged(propertyName);
        }
        return needChange;
    }
    protected void OnPropertyChanging(string propertyName)
    {
        PropertyChangingEventHandler handler = PropertyChanging;
        if (handler != null)
            handler(this, new PropertyChangingEventArgs(propertyName));
    }
    protected void OnPropertyChanged(string propertyName)
    {
        PropertyChangedEventHandler handler = PropertyChanged;
        if (handler != null)
            handler(this, new PropertyChangedEventArgs(propertyName));
    }
    #endregion
}

编辑-变通

我已经能够找到一个工作，但它闻起来…我使用BackgroundWorker来"退出"更改事件，之后我执行单击虚拟按钮。

    private void checkBox1_CheckedChanged(object sender, EventArgs e)
    {
        //Wont work, need to get out of this event.
        //btnDummy.PerformClick();
        //Using another thread to get out of this event:
        RunAsyncBindFixer();
    }
    private void RunAsyncBindFixer()
    {
        var workerBindFixer = new BackgroundWorker();
        workerBindFixer.DoWork += WorkerBindFixer_DoWork;
        workerBindFixer.RunWorkerCompleted += WorkerBindFixer_RunWorkerCompleted;
        Console.WriteLine("Starting RunAsyncBindFixer");
        workerBindFixer.RunWorkerAsync();
    }
    void WorkerBindFixer_DoWork(object sender, DoWorkEventArgs e)
    {
        //Aparently we need nothing here.
        //Thread.Sleep(0);
    }
    void WorkerBindFixer_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        Console.WriteLine("RunAsyncBindFixer RunWorkerCompleted");
        btnDummy.PerformClick();
        //Checked change on a dummy checkbox wont work also
        //ckbDummy.Checked = !ckbDummy.Checked;
        Console.WriteLine("Dummy action applied");
    }

checkBox1.DataBindings.Add("Checked", car, "IsOnSale", true, DataSourceUpdateMode.OnPropertyChanged);