当属性字段在内部更改时，INotifyPropertyChanged 不起作用

Question

我尝试将文本块用户控件与我的类的属性绑定，但它只在初始阶段有效，我已经在我的类中实现了 IPropertyChnaged。

在我的课堂上，_Feedbackpos（属性字段）会在后台发生变化，我不知道如何解决这个问题。

我的班级

public class TestControl : INotifyPropertyChanged
{
  public event PropertyChangedEventHandler PropertyChanged;
  private void NotifyPropertyChanged(string propertyname)
  {
     if(PropertyChanged != null)
     {
        PropertyChanged(this, new PropertyChangedEventArgs(propertyname));
     }
  }

  private double _Feedbackpos;
  public double Feedbackpos
  {
     get 
     {
       return _Feedbackpos;
     }
     set
     {
       _Feedbackpos = value;
       NotifyPropertyChanged("Feedbackpos");
     }
  }

  //it's a callback function, it would excute when detect feedback position of controller change
  private void ReadFeedbackpos()
  {
    _Feedbackpos = Controller.Read();
  }

}

应用程序窗口

TestControl TestDll = new TestControl();

Binding BindingTxtBlk = new Binding(){Source= TestDll, Path = new Property("Feedbackpos")};

FeedbackPosTxtBlk.Setbinding(Textblock.TextProperty,BindingTxtBlk);

Answer 1

将函数ReadFeedbackpos()改为

private void ReadFeedbackpos()
{
    Feedbackpos = Controller.Read();
}

否则NotifyPropertyChanged("Feedbackpos"); 将永远不会被调用。