我有这个静态辅助函数:
public static DependencyObject GetParentObject(DependencyObject child)
{
if (child == null) return null;
ContentElement contentElement = child as ContentElement;
if (contentElement != null)
{
var parent = ContentOperations.GetParent(contentElement);
if (parent != null) return parent;
var fce = contentElement as FrameworkContentElement;
return fce != null ? fce.Parent : null;
}
//if it's not a ContentElement, rely on VisualTreeHelper
return VisualTreeHelper.GetParent(child);
}
它在真实应用中能够工作,但是我想为它编写一些单元测试。这是我的第一次尝试:
[Test]
public void GetParentObject_returns_immediate_parent()
{
var contentControl = new ContentControl();
var textBox = new TextBox();
contentControl.BeginInit();
contentControl.Content = textBox;
contentControl.EndInit();
var result = UIHelper.GetParentObject(textBox);
Assert.AreSame(contentControl, result);
}
很不幸,它失败了,因为VisualTreeHelper
返回了null。我该如何模拟一个可行的可视化树?
pageContent
强制转换为IAddChild
并直接执行了操作,而不依赖于ToMaybeOf
和Do
:((IAddChild)pageContent).AddChild(fixedPage);
- David Meredith