我刚刚为我的站点解决了此问题(尝试确定托管您的应用程序的DNX进程的进程ID时发生错误")-相同，正在升级从Beta 7到RC1.我相信这些项目最初是在Beta 4或5中创建的.

I just solved this issue for my sites ("An error occurred attempting to determine the process id of the DNX process hosting your application") - same boat, upgrading from Beta 7 to RC1. I believe these projects were originally created in Beta 4 or 5.

事实证明，较早版本的ASP.Net beta版在我的web.config中存在额外的垃圾，这些垃圾掩盖了请求.

It turns out there was extra garbage in my web.config from earlier versions of the ASP.Net beta, and these were mucking up the request.

我删除了这些:

  <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
  <remove name="OPTIONSVerbHandler" />
  <remove name="TRACEVerbHandler" />
  <add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />

这些站点开始在IIS Express中正常运行.如果这对您不起作用，您可以尝试创建一个新项目并查看其是否正常工作-比较web.config，startup和project.json文件，以查看是否需要进行其他更改.

And the sites began running appropriately in IIS Express. If this doesn't work for you, you might try creating a new project and seeing if it works correctly - compare the web.config, startup, and project.json files to see if there are any other changes you need to make.