Question

我是WPF的新手，过去几天我一直在打破这个问题。我试图将文本框的基本绑定设置为字符串属性。我按照MS教程，但似乎没有任何工作。

这是电子邮件类，我正在尝试将其主题属性绑定到文本框中显示

public class Email : INotifyPropertyChanged
{
    private string _subject;

    public string Subject
    {
        get { return _subject; }
        set
        {
            _subject = value;
            OnPropertyChanged("Subject");
        }
    }

    private string _contents;

    public string Contents
    {
        get { return _contents; }
        set
        {
            _contents = value;
            OnPropertyChanged("Contents");
        }
    }

    private Category _category;

    public Category Category
    {
        get { return _category; }
        set
        {
            _category = value;
            OnPropertyChanged("Category");
        }
    }

    public Email()
    {
    }

    public event PropertyChangedEventHandler PropertyChanged;

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

这是UserControl中的电子邮件设置器，它们是文本框的父级：

private Email _email;

public Email Email
{
    get { return _email; }
    set
    {
        _email = value;
        if (_email != null)
        {
            Binding myBinding = new Binding("Subject");
            myBinding.Source = _email;
            tbSubject.SetBinding(TextBlock.TextProperty, myBinding);
        }
    }
}

tbSubject永远不会被设置为任何东西，即使传递的电子邮件不是null并且有主题，它也总是空的！如果我这样做：

public Email Email
{
    get { return _email; }
    set
    {
        _email = value;
        if (_email != null)
        {
            tbSubject.Text = _email.Subject;
        }
    }
}

它工作正常。我不明白我做错了什么。

Answer 1

我想我已经明白了。这是我必须做出的改变：

    public partial class EmailContentsTemplate : UserControl, INotifyPropertyChanged
{
    private Email _email;

    public Email Email
    {
        get { return _email; }
        set
        {
            _email = value;
            OnPropertyChanged("Email");
        }
    }


    public EmailContentsTemplate()
    {
        InitializeComponent();

        DataContext = this;

        Binding myBinding = new Binding("Email.Subject");
        myBinding.Source = this;
        tbSubject.SetBinding(TextBlock.TextProperty, myBinding);
    }

    public event PropertyChangedEventHandler PropertyChanged;

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

所以我将源代码改为＆＃34;这个＆＃34;并使用户控件实现INotifyPropertyChanged。现在它有效。

或者我通过XAML

开始工作

<TextBox x:Name="tbSubject" Grid.Column="1" Grid.Row="1" Margin="3" Text="{Binding Email.Subject}"/>

WPF基本绑定不起作用

1 个答案: