WPF单向绑定：更新源上的属性已更改[重复]

Question

我有一个初学者问题。也许我很困惑，并没有完全弄清楚绑定概念。

我尝试使用绑定，但是当我更改源值时，我在文本框上看不到任何更新。

XLAM 文件：

<TextBox IsReadOnlyCaretVisible="True" AutomationProperties.Name="keyIdTextBox" Text="{Binding Path=Name, Mode=oneWay}"/>

...

<Button Content="Open" AutomationProperties.Name="openCloseButton" Click="OpenClose_Click"/>

C# 文件：

public class Person
{
    private string nameValue;
    public string Name
    {
        get { return nameValue; }
        set { nameValue = value; }
    }
}


/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window
{
    private Person person = new Person { Name = "Bob" };

    public MainWindow()
    {
        InitializeComponent();
        this.DataContext = person;
    }


    private void OpenClose_Click(object sender, RoutedEventArgs e)
    {
        person.Name = "Lenny";
    }

在开始时，文本框更新良好并显示“Bob”，但是当我单击按钮更新名称的值时，文本框不反映值“Lenny”。没有变化。

感谢您的帮助。

Answer 1

选项 1：INotifyPropertyChanged

Person 类应实现INotifyPropertyChanged 接口，以便在属性更改时通知目标。

这是修改后的工作示例。

public class Person : INotifyPropertyChanged
{
    private string nameValue;

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

    public event PropertyChangedEventHandler PropertyChanged;

    protected virtual void OnPropertyChanged([CallerMemberName] string propertyName = null)
    {
        PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
    }
}

public partial class MainWindow : Window
{
    private Person person = new Person { Name = "Bob" };

    public MainWindow()
    {
        InitializeComponent();
        this.DataContext = person;
    }

    private void OpenClose_Click(object sender, RoutedEventArgs e)
    {
        person.Name = "Lenny";
    }
}

选项 2：DependencyProperty

将Name 属性定义为DependencyProperty。基础架构将处理这些更改。

看看下面的例子。

public class Person : DependencyObject
{
    public static readonly DependencyProperty
        NameProperty = DependencyProperty.Register("Name", typeof(string), typeof(Person));

    public string Name
    {
        get => (string)GetValue(NameProperty);
        set => SetValue(NameProperty, value);
    }
}

public partial class MainWindow : Window
{
    private Person person = new Person { Name = "Bob" };

    public MainWindow()
    {
        InitializeComponent();
        this.DataContext = person;
    }

    private void OpenClose_Click(object sender, RoutedEventArgs e)
    {
        person.Name = "Lenny";
    }
}