IIS8.5 WEB API program, problems encountered

# #IIS7/8 HTTP error 500.19 errors 0x80070021
iis7.0/8.0 Error HTTP Errors 500.19-internal Server error code 0x80070021, probably because the security settings for IIS7.0 are significantly changed compared to the previous version. IIS7.0 security settings file in%windir%\system32\inetsrv \config\ ApplicationHost.config, this defines the security settings for all Web programs, which can be overridden by the Web. config in each of the various websites, but is not allowed by default.

So first modify the ApplicationHost.config file, open the permissions of handlers and modules, that is, change from deny to allow, as follows:

<configuration> <configSections> <sectiongroup name= "system.webserver" > ... <section name= " Handlers "overridemodedefault=" Allow "/> ... <section name=" modules "allowdefinition=" MachineToApplication " overridemodedefault= "Allow"/> ...

In addition, if IIS7.0 is installed after the VS installation, you need to add IIS7.0 support for the ASP. aspx file will not recognize the MIME error, or the above problem.

Method: Open and close system functions---Internet Information Services--"Web Services---" Application development Function-"Check ASP.
In general, this situation is more!

# #应用池没有 reasons for net4.5.
The normal establishment of the deployment site, but the problem is the installation habit, you have to let me choose the framework of the. NET Framework 4.5 Ah, but the hell is not ah
. NET 4.5 is a in-place replacement for. NET 4.0,

When. NET 4.5 was installed it effectively replaces. NET 4.0 on the machine. . NET 4.0 gets overwritten by a new version of. NET 4.5 which-according to Microsoft-is supposed to be 100% backwards C Ompatible.

Our simple understanding is that 4.5 is essentially 4.0, which is an incremental update, so it's only 4.0 for IIS to see the version number in the 4.5 DLL library below.