WPF FrameworkPropertyMetaData 日志 — 这有什么意义？

Question

Basically, just as the title asks:

What is the point of the Journal property? MSDN doesn't really explain it's actual usefulness.

Answer 1

This is nicely explained by this blog post , or on the official MSDN page .

To summarize though:

Windows Presentation Foundation (WPF) supports browser-style navigation that can be used in two types of applications: standalone applications and XAML browser applications (XBAPs). To package content for navigation, WPF provides the Page class. You can navigate from one Page to another declaratively, by using a Hyperlink, or programmatically, by using the NavigationService. WPF uses the journal to remember pages that have been navigated from and to navigate back to them.
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If you need to remember small pieces of state across Page navigations, you can use dependency properties (see DependencyProperty) that are configured with the FrameworkPropertyMetadata.Journal metadata flag.