WPF MVVM：绑定可见性不起作用

Question

我无法通过代码更改UserControl的可见性。有人知道为什么吗？

<Window.Resources>
    <BooleanToVisibilityConverter x:Key="BoolToVisConverter" />
</Window.Resources>

<Viewbox Stretch="Fill">
    <Grid Background="#FF191919">
        <local:UserView Visibility="{Binding UserViewVisible, Converter={StaticResource BoolToVisConverter}}" 
                        HorizontalAlignment="Center" 
                        Height="740" 
                        VerticalAlignment="Center" 
                        Width="1290" 
                        Margin="0,0,0,0"/>
    </Grid>
</Viewbox>

C＃：

class MainWindowViewModel : BindableBase
{

    private bool userViewVisible = true;
    public bool UserViewVisible
    {
        get { return userViewVisible; }
        set { userViewVisible = value; RaisePropertyChanged("UserViewVisible"); }
    }

    public MainWindowViewModel()
    {
        UserViewVisible = false;
    }

}

代码正在编译，只是无法正常工作。我不能在构造函数中更改此可见性。我还检查了-绑定设置正确。我不知道为什么这不起作用。我正在寻找20分钟的错字。

我的绑定代码：

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        MainWindowViewModel vm = new MainWindowViewModel();
        this.DataContext = vm;
    }
}