约束问题

Question

XAML

<TextBlock Grid.Column="1"
                   Height="37"
                   Margin="8,17,0,0"
                   HorizontalAlignment="Left"
                   VerticalAlignment="Top"
                   FontSize="20"
                   Text="{Binding Contact.Name,
                                  UpdateSourceTrigger=PropertyChanged}" />

C＃ XAML

背后的代码

public partial class Conversation : Window
{

    private Friend _Contact;
    public Friend Contact
    {
        get
        {
            return _Contact;
        }
        set
        {
            _Contact = value;
            OnPropertyChanged ( "Contact" );
        }
    }


    #region INotifyPropertyChanged Members

    public event PropertyChangedEventHandler PropertyChanged;

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

    #endregion


    public Conversation ( Friend _Friend )
    {
        InitializeComponent ( );

        Contact = _Friend;
    }

    .
    .
    .

}

C＃朋友类

public class Friend : Person
{

    .
    .
    .

}

C＃人员类

public class Person : INotifyPropertyChanged 
{       

    private string _Name;

    public string Name
    {
        get
        {
            return _Name;
        }
        set
        {
            _Name = value;
            OnPropertyChanged ( "Name" );
        }


    #region INotifyPropertyChanged Members

        public event PropertyChangedEventHandler PropertyChanged;

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

    #endregion


    .
    .
    .


}

我的问题：为什么绑定不起作用？

Answer 1

联系人需要是财产而不是领域。

此外，您需要更改绑定，以便源是窗口类。

Answer 2

正如wangberger所说，联系必须是财产。

正如wangberger暗示的那样，你没有将绑定目标（TextBlock控件）或其任何祖先（例如窗口）的DataContext设置为绑定源（在你的情况下是窗口本身）。

另外，请阅读Microsoft关于命名约定的.NET指南。

P.S。如果值为！= _name;

，Setter应该只提升PropertyChanged