绑定不响应PropertyChanged

Question

I have a model and a view-model for a Window and I'm stuck with view.
The view has a control that has the following Content:

<TextBlock Text="{Binding Title}" [...] />

The data-context is the view-model, which has a Title property of type string.

The issue is that even when the value changes (and I can see it does through the debugger) and PropertyChanged is called for the Title , the TextBlock doesn't change (it stays empty).

To confirm this I've actually called an update method on every mouse press.

I've heard sometimes the binding in TextBlock s are bugged so I've also tried a Label but it didn't work. Any suggestions? If there's any code you want to see please tell me in the comments (the whole thing is pretty big).

ViewModel
Code-behind for the View.

To be clearer: Window is my model, and not WPF's Window!

Answer 1

Your _window.Title is string.Empty . Assign some value to it. Like

public WindowViewModel()
{
    Window = new Window(){Title="abc"};
}

Update I tried your code but it didnt work for me I did one change and it worked the change is

public WindowEntryView()
{
    DataContext = new WindowViewModel();
    InitializeComponent();
}

Answer 2

It would work if you instantiate your WindowViewModel class

CodeBehind:

public partial class WindowEntryView
{
    public static readonly DependencyProperty WindowViewModelProperty;
    public WindowViewModel WindowViewModel
    {
        get { return (WindowViewModel)GetValue(WindowViewModelProperty); }
        set
        {
            SetValue(WindowViewModelProperty, value);
            value.Refresh(); // I've putted this out of desperation to see if it would help.. it didn't.
        }
    }

    static WindowEntryView()
    {
        PropertyMetadata metadata = new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.AffectsRender); // Another attempt with no success.
        WindowViewModelProperty = DependencyProperty.Register("WindowViewModel", typeof(WindowViewModel), typeof(WindowEntryView), metadata);
    }

    public WindowEntryView()
    {
        //WindowViewModel = new WindowViewModel(19860522); This is the only attempt that made the label show something, but it didn't update later of course.

        InitializeComponent();

        WindowViewModel = new WpfApplication3.WindowViewModel() { Title = "Check" };
        DataContext = WindowViewModel;
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        WindowViewModel.Title = DateTime.Now.ToString();
    }
}

XAML:

<Grid>
    <TextBlock Text="{Binding Title}" VerticalAlignment="Top"/>
    <Button Content="Button" HorizontalAlignment="Left" Margin="116,131,0,0" VerticalAlignment="Top" Width="75" Click="Button_Click"/>
</Grid>

Answer 3

您可以将属性名称（在您的情况下为“标题”）传递给OnPropertyChanged方法。