如何访问ListBoxItems的Visibility属性

在我的WPF程序中,我有一个ListBox控件:

     

如何访问ListBoxItems Visibility属性? 我的代码不起作用:

 mailsListBox.Items[1].Visibility = Visible; 

像这样:

 (mailsListBox.Items[1] as ListBoxItem).Visibility = Visibility.Visible; 

或者您可以使用ItemContainerGenerator.ContainerFromItem方法:

 ((ListBoxItem)(mailsListBox.ItemContainerGenerator.ContainerFromItem(mailsListBox.Items[1]))).Visibility = Visibility.Visible;