如何将简单的.net属性绑定到标签并让它自动更新

Question

我对数据绑定有点新鲜,显然不太了解它.我正在尝试将一个简单的.net属性绑定到一个标签,并在更改属性时更新该标签.它不起作用,我不确定问题出在哪里.

这是我的XAML

 <Label Content="{Binding Path=Name, UpdateSourceTrigger=PropertyChanged}"></Label>

 <Button Name="bChangeProperty" Click="bChangeProperty_Click">Change Property</Button>

这是我的UserControl cs文件

public partial class MyUserControl : UserControl, INotifyPropertyChanged
{

   private MyObjectClass _myObject;
   public MyObjectClass MyProperty
   {
       get { return _myObject;}
       set
       {
          if (_myObject != value)
          {
              _myObject = value;
              OnPropertyChanged("MyProperty"); 
          }
        }
   }


   public MyUserControl(MyObjectClass obj)
   {
      if (obj == null)
      {
          obj = new MyObjectClass();
          obj.Name = "Frank";
      }
      MyProperty= obj;
      base.DataContext = MyProperty;
   }

   //INotifyPropertyChanged stuff
   public event PropertyChangedEventHandler PropertyChanged;
   private void OnPropertyChanged(string propertyName)
   {
      //PropertyChanged is always null, don't really understand this part
      if (PropertyChanged != null)
         PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
   }


   private void bChangeProperty_Click(object sender, RoutedEventArgs e)
   {
       //Create a new object, and set it to the MyProperty Property - which I thought
       //would update the label, but it doesn't
       MyObjectClass newObject = new MyObjectClass();
       newObject.Name = "Bob";

       MyProperty= newObject;
   }

这是MyObjectClass

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

初始绑定有效,它会将Label设置为"Frank",但是当我单击按钮并更改对象时,标签将不会更新.这只是我喜欢做的事情的一个例子.

我必须将PropertyChanged设置为某个地方吗？我有点想到这就是XAML想要做的事情,但看看它总是如何无效,显然它不是.

Answer 1

您需要实现INotifyPropertyChanged上MyObjectClass和火灾PropertyChanged之后MyObjectClass.Name发生了变化.

public class MyObjectClass : INotifyPropertyChanged
{
    private string name;

    public string Name 
    {
        get
        {
            return this.name;
        }
        set
        {
            this.name = value;
            OnPropertyChanged("Name"); 
        } 
    }

    public event PropertyChangedEventHandler PropertyChanged;

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