internal static object AddVirtualPathToFileMapping(VirtualPath virtualPath, string physicalPath)
     CallContext.SetData(GetFixedMappingSlotName(virtualPath), physicalPath);
     VirtualPathToFileMappingState state = new VirtualPathToFileMappingState {
         VirtualPath = virtualPath,
         VirtualPathProvider = _theHostingEnvironment._virtualPathProvider
     _theHostingEnvironment._virtualPathProvider = _theHostingEnvironment._mapPathBasedVirtualPathProvider;
     return state;
         * Map a virtual path to a physical path.  i.e. the physicalPath will be returned
         * when MapPath is called on the virtual path, bypassing the IApplicationHost
        internal static object AddVirtualPathToFileMapping(
            VirtualPath virtualPath, string physicalPath) {

            // Save the mapping in the call context, using a key derived from the
            // virtual path.  The mapping is only valid for the duration of the request.
            CallContext.SetData(GetFixedMappingSlotName(virtualPath), physicalPath);

            // Return a mapping object to keep track of the virtual path, and of the current
            // virtualPathProvider.
            VirtualPathToFileMappingState state = new VirtualPathToFileMappingState();
            state.VirtualPath = virtualPath;
            state.VirtualPathProvider = _theHostingEnvironment._virtualPathProvider;

            // Always use the MapPathBasedVirtualPathProvider, otherwise the mapping mechanism
            // doesn't work (VSWhidbey 420702)
            // Set/Get the VPP on the call context so as not to affect other concurrent requests  (Dev10 852255)
            CallContext.SetData(TemporaryVirtualPathProviderKey, _theHostingEnvironment._mapPathBasedVirtualPathProvider);

            return state;