C# wpf如何从自定义标题栏获取视图属性

我有一个名为bar1.xaml的自定义标题栏，它由名为WindowBase.xaml的局部视图引用

<ResourceDictionary.MergedDictionaries>
    <ResourceDictionary Source="/Project1;component/Themes/WPFThemes/Bar1.xaml" />
</ResourceDictionary.MergedDictionaries>

从调试器中，当我指向窗口时，我可以看到字段值，但我无法在代码中访问它们。有办法吗

我尝试了x:FieldModifier=“public”，但它不起作用

    <Button Content="Start"  Name="start" IsEnabled="{Binding StartIsEnabled}" Command="{Binding StartCommand}" Visibility="{Binding StartVisibility}" x:FieldModifier="public"/>

谢谢

private void CloseButton_Click(object sender, RoutedEventArgs e)
{
  Window window = this.TemplatedParent as Window;
} 

    <Button Content="Start"  Name="start" IsEnabled="{Binding StartIsEnabled}" Command="{Binding StartCommand}" Visibility="{Binding StartVisibility}" x:FieldModifier="public"/>