在ASP.Net MVC中使用布局页面时，是否在每次调用新页面时加载布局？

Question

I'm just curious to know, because I'm still learning layout pages, if when I use a layout page (ex. SiteLayout.cshtml) and have two pages getting rendered with it (Index.cshtml, Results.cshtml) in the @RenderBody() section, does the layout wrapper part get loaded each time I go between Index.cshtml and Results.cshtml? Or does the _layout.cshtml page load the @Renderbody() section asynchronously?

Just to throw in some example pics

Answer 1

Unless you've setup donut caching ( http://weblogs.asp.net/scottgu/tip-trick-implement-donut-caching-with-the-asp-net-2-0-output-cache-substitution-feature ), the SiteLayout.cshtml will get executed separately for every page.

If your SiteLayout has some long/expensive operation and you don't want it loading every time, you can use the aforementioned donut caching to have it execute once per user per X amount of time.

If you want the SiteLayout to start sending data to the browser before the body is done executing/rendering (ie asynchronously for overall speed purposes), you can use a nuget package called CourtesyFlush ( http://www.hanselman.com/blog/NuGetPackageOfTheWeekCourtesyFlushToFlushBuffersEarlierAndOptimizeTimeToFirstByte.aspx )