IIS 7.5 applicationHost.config file is not being updated - iis-7.5

Question

I'm currently playing around with the Microsoft.Web.Administration (MWA) namespace in order to adjust our application to configure IIS 7.5 with the new API.
I understood that all IIS level changes should be expressed in the following file (I'm on Win2K8-R2):
%WINDIR%\System32\inetsrv\config\applicationHost.config
So, when I use the ServerManager object to commit the configuration changes the file should be updated accordingly.
After adding a new MIME type (programmatic with MWA) I did not see any changes in the applicationHost.config file, but I do see the new MIME type in the IIS manager window and IIS recognizes this MIME type without problems. Even after restating the OS - The config file does not contain the newly added MIME type, but the IIS manager window does list it.
Because my application pools are forced to 32-bit (Enable32BitAppOnWin64 = true), I thought that the related config file should be located under %WINDIR%\SysWOW64\inetsrv\Config, but (if it exists...) - it also does not change after the code commits the updates.
Can someone please explain this? Am I missing something (looking at the wrong file maybe?)? Can someone please shed some light on the SysWOW64\inetsrv\config directory?
This is my code for adding the MIME type:
ServerManager manager = new ServerManager();
ConfigurationElementCollection staticContentCollection = manager
.GetApplicationHostConfiguration()
.GetSection("system.webServer/staticContent")
.GetCollection();
//MIMETypes is a string[] array, each object is {FileExt},{MIMETypeStr}
foreach (string pair in MIMETypes)
{
string[] mimeProps = pair.Split(',');
ConfigurationElement mimeTypeEl = staticContentCollection
.Where(a =>
(string)a.Attributes["fileExtension"].Value == mimeProps[0])
.FirstOrDefault();
if (mimeTypeEl != null)
{
staticContentCollection.Remove(mimeTypeEl);
}
ConfigurationElement mimeMapElement =
staticContentCollection.CreateElement("mimeMap");
mimeMapElement["fileExtension"] = mimeProps[0];
mimeMapElement["mimeType"] = mimeProps[1];
staticContentCollection.Add(mimeMapElement);
}
manager.CommitChanges();
//At this point all is working but the config file does not reflect the change

Answer 1

I just tried your code and it works fine. You are aware that this mime type is being added to the global mime type collection and not to a site?
It also gets added to the end of the <staticContent> list, this list isn't re-sorted when you do ServerManager.CommitChanges().
Also on Windows 2008-R2 the correct location for applicationHost.config is at:
C:\Windows\System32\inetsrv\config
I'm guess you're either using notepad.exe or NotePad2 to open this file (32 bit editors can't open it). Notepad won't reload the file upon a change and NotePad2 needs to be told to display a file change notification (alt-F5), out of the box it won't.
Also try adding something unusual like .xxx, run your update then open the config file and do a search. I guarantee it'll be there.
Update:
Further to your comments below, I'm not sure how you're able to open applicationHost.config using NotePad++ or any 32-bit editor, I certainly can't. Can you download NotePad2 which is a 64-bit editor:
http://www.flos-freeware.ch/notepad2.html
The release candidate works just fine.
On a default install of any 64 bit Windows 2008 or Windows 7 there shouldn't be an applicationHost.config in the C:\Windows\SysWOW64\inetsrv\Config folder. I'm not sure why you'd be seeing one there.

Answer 2

As a workaround to open and edit the 64-bit IIS configuration files with your favorite 32-bit editor that is 64-bit compatible (i.e. Notepad++), you can create a Windows directory symbolic link which points to C:\Windows\System32\inetsrv\Config. With this method, you are replacing the 32-bit Config directory, located at C:\Windows\SysWOW64\inetsrv\Config to point to the 64-bit version. If, for example, you have an application which requires both 32-bit and 64-bit versions, this method won't work.
For more information, I strongly encourage you to visit this MSDN Blog.