Question

我想访问绑定到视图模型中文本框的依赖项属性。在视图模型中，我有以下代码：

Answer _Answer = new Answer();
_Answer.GetValue(Answer.Deutsch1AnswerProperty);
Console.WriteLine(_Answer.Deutsch1Answer);

依赖属性定义如下：

public class Answer : DependencyObject
{
    // Ereignis
    public event EventHandler Deutsch1AnswerChanged;

    public static readonly DependencyProperty Deutsch1AnswerProperty;

    public String Deutsch1Answer
    {
        get { return (String)GetValue(Deutsch1AnswerProperty); }
        set { SetValue(Deutsch1AnswerProperty, value); }
    }

    public static void OnDeutsch1AnswerChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e)
    {
        Answer _Answer = (Answer)sender;
        if (_Answer.Deutsch1AnswerChanged != null)
            _Answer.Deutsch1AnswerChanged(_Answer, null);
    }

    static Answer()
    {
        FrameworkPropertyMetadata meta = new FrameworkPropertyMetadata(string.Empty, FrameworkPropertyMetadataOptions.AffectsRender | FrameworkPropertyMetadataOptions.BindsTwoWayByDefault);
        meta.PropertyChangedCallback = new PropertyChangedCallback(OnDeutsch1AnswerChanged);

        Deutsch1AnswerProperty = DependencyProperty.Register("Deutsch1Answer", typeof(String), typeof(Answer), meta);
    }
}

在MainWindow.Xaml中我有以下代码：

<Window.Resources>
    <local:Answer x:Key="_Answer" Deutsch1Answer=string.Empty />
</Window.Resources>
<Grid Definitions ...>
   <TextBox Grid.Column="1" Grid.Row="2" Name="BoxDeutsch1" Text="{Binding Source={StaticResource _Answer}, Path=Deutsch1Answer}">
    </TextBox>

我无法访问视图模型中的Text属性。请帮忙。

视图模型如下所示：

public class VokabelViewModel : INotifyPropertyChanged
{
    private Vokabel _Model;
    public VokabelViewModel(Vokabel model)
    {
        _Model = model;
    }

    private ICommand _boxDeutsch1_HitEnter;
    public ICommand BoxDeutsch1_HitEnter
    {
        get
        {
            return _boxDeutsch1_HitEnter ?? (_boxDeutsch1_HitEnter = new CommandHandler(() => MyActionBoxDeutsch1_HitEnter(), _canExecuteBoxDeutsch1_HitEnter));
        }
    }
    private bool _canExecuteBoxDeutsch1_HitEnter;
    public void MyActionBoxDeutsch1_HitEnter()
    {
        Answer _Answer = new Answer();
        _Answer.GetValue(Answer.Deutsch1AnswerProperty);
        _Model.TestVokabel(_Answer.Deutsch1Answer);
    }

Answer 1

如果要访问ViewModel中的Deutsch1Answer DependencyProperty，则应绑定它。但是，我真的没有看到你为什么得到＆＃34;答案＆＃34; -class。

如果要将文本框文本绑定到视图模型中的属性，则应添加Answer属性并将其直接绑定到文本框。

在ViewModel中：

private string m_answer;

public string Answer
{
  get { return m_answer; }
  set 
    { 
      m_answer = value;
      OnPropertyChanged("Answer");
    }
}

在您的视图中：

...
<TextBox Grid.Column="1" Grid.Row="2" Name="BoxDeutsch1" Text="{Binding Answer}">
...

如何在视图模型中访问绑定到依赖项属性的文本？

1 个答案: