Using Managed Code to Detect if IIS is Installed and ASP/ASP.NET is Registered

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Introduction

My earlier article [^] on detecting what .NET Framework versions and service packs are installed using managed code generated some follow up questions related to detecting if Internet Information Services (IIS) is installed and if ASP or ASP.NET is registered.

Since this is a managed code solution, it does require that a version of the .NET Framework is already installed, so this class is not guaranteed to work as part of an installation process. If you need to do this reliably from an installation process, you need to look at doing the same work using unmanaged C++.

Background

The correct way to determine if a specific version of Internet Information Services is installed is to look in the registry for the following key:

HKLM\Software\Microsoft\InetStp\MajorVersion

This is a DWORD value that indicates the version of IIS installed, if it exists.

For IIS 5, you can use the MinorVersion DWORD value to determine if you are running on Windows 2000 Server or Windows XP Professional. If MinorVersion is 1, then you are running on Windows XP Professional.

Detecting IIS Subcomponents

Sometimes, just knowing if IIS is installed isn't enough and you need to determine if specific subcomponents are also installed. Again, we can turn to the registry for this information. All of the subcomponent information is contained in the following registry key:

HKLM\Software\Microsoft\Microsoft\Windows\CurrentVersion\Setup\Oc Manager\Subcomponents

All of the values under this key are DWORDs, so if the value is 1 then that component is installed.

Detecting if ASP or ASP.NET is Registered

In order to detect if ASP is registered with IIS, you can simply look to see if the ASP component (iis_asp) is installed. However, for ASP.NET it becomes a little bit more involved since there are different versions of ASP.NET. We can also use the registry for this information, by looking at the following keys:

If the key exists, then that version of ASP.NET is registered with IIS.

Using the Code

In order to consolidate checking all of the various registry keys and help isolate changes for future versions of the .NET Framework and IIS, the InternetInformationServicesDetection class was created. This class exposes the following public methods:

• public static bool IsInstalled(InternetInformationServicesVersion iisVersion)

• public static bool IsInstalled(InternetInformationServicesComponent subcomponent)

• public static bool IsAspRegistered()

• public static bool IsAspNetRegistered(FrameworkVersion frameworkVersion)

As you can see, these functions use the FrameworkVersion, InternetInformationServicesVersion, and InternetInformationServicesComponent enumerations. These enumerations have the following definition:

/// <summary>
/// Specifies the .NET Framework versions
/// </summary>
public enum FrameworkVersion
{
   /// <summary>
   /// .NET Framework 1.0
   /// </summary>
   Fx10,

   /// <summary>
   /// .NET Framework 1.1
   /// </summary>
   Fx11,

   /// <summary>
   /// .NET Framework 2.0
   /// </summary>
   Fx20,

   /// <summary>
   /// .NET Framework 3.0
   /// </summary>
   Fx30,

   /// <summary>
   /// .NET Framework 3.5 (Orcas)
   /// </summary>
   Fx35,
}

/// <summary>
/// Specifies the Internet Information Services (IIS) versions
/// </summary>
public enum InternetInformationServicesVersion
{
  /// <summary>
  /// Internet Information Services 4
  /// </summary>
  /// <remarks>Shipped in NT Option Pack for Windows NT 4</remarks>
  IIS4,

  /// <summary>
  /// Internet Information Services 5
  /// </summary>
  /// <remarks>Shipped in Windows 2000 Server and Windows XP Professional</remarks>
  IIS5,

  /// <summary>
  /// Internet Information Services 6
  /// </summary>
  /// <remarks>Shipped in Windows Server 2003</remarks>
  IIS6,

  /// <summary>
  /// Internet Information Services 7
  /// </summary>
  /// <remarks>Shipped in Windows Vista</remarks>
  IIS7,
}

/// <summary>
/// Specifies the Internet Information Services (IIS) versions
/// </summary>
public enum InternetInformationServicesComponent
{
  /// <summary>
  /// Internet Information Services Common Files
  /// </summary>
  Common,

  /// <summary>
  /// Active Server Pages (ASP) for Internet Information Services
  /// </summary>
  ASP,

  /// <summary>
  /// File Transfer Protocol (FTP) service
  /// </summary>
  FTP,

  /// <summary>
  /// Internet Information Services Manager
  /// </summary>
  InetMgr,

  /// <summary>
  /// Internet Data Connector
  /// </summary>
  InternetDataConnector,

  /// <summary>
  /// Network News Transfer Protocol (NNTP) service
  /// </summary>
  NNTP,

  /// <summary>
  /// Server-Side Includes
  /// </summary>
  ServerSideIncludes,

  /// <summary>
  /// Simple Mail Transfer Protocol (SMTP) service
  /// </summary>
  SMTP,

  /// <summary>
  /// Web Distributed Authoring and Versioning (WebDAV) publishing
  /// </summary>
  WebDAV,

  /// <summary>
  /// World Wide Web (WWW) service
  /// </summary>
  WWW,

  /// <summary>
  /// Remote administration (HTML)
  /// </summary>
  RemoteAdmin,

  /// <summary>
  /// Internet Server Application Programming Interface (ISAPI) for
  /// Background Intelligent Transfer Service (BITS) server extensions
  /// </summary>
  BitsISAPI,

  /// <summary>
  /// Background Intelligent Transfer Service (BITS) server extensions
  /// </summary>
  Bits,

  /// <summary>
  /// FrontPage server extensions
  /// </summary>
  FrontPageExtensions,

  /// <summary>
  /// Internet printing
  /// </summary>
  InternetPrinting,

  /// <summary>
  /// ActiveX control and sample pages for hosting Terminal Services
  /// client connections over the web
  /// </summary>
  TSWebClient,
}

A complete example in C# looks like this:

bool iis4Installed =
    InternetInformationServicesDetection.IsInstalled
        (InternetInformationServicesVersion.IIS4);

bool iis5Installed =
    InternetInformationServicesDetection.IsInstalled
        (InternetInformationServicesVersion.IIS5);

bool iis6Installed =
    InternetInformationServicesDetection.IsInstalled
        (InternetInformationServicesVersion.IIS6);

bool iis7Installed =
    InternetInformationServicesDetection.IsInstalled
        (InternetInformationServicesVersion.IIS7);


Console.WriteLine("IIS 4 installed? {0}", iis4Installed);
Console.WriteLine("IIS 5 installed? {0}", iis5Installed);
Console.WriteLine("IIS 6 installed? {0}", iis6Installed);
Console.WriteLine("IIS 7 installed? {0}", iis7Installed);

if (iis4Installed || iis5Installed || iis6Installed || iis7Installed)
{
    Console.WriteLine("ASP Registered? {0}",
        InternetInformationServicesDetection.IsAspRegistered());

    Console.WriteLine("ASP.NET 1.0 Registered? {0}",
        InternetInformationServicesDetection.IsAspNetRegistered(FrameworkVersion.Fx10));

    Console.WriteLine("ASP.NET 1.1 Registered? {0}",
        InternetInformationServicesDetection.IsAspNetRegistered(FrameworkVersion.Fx11));

    Console.WriteLine("ASP.NET 2.0 Registered? {0}",
        InternetInformationServicesDetection.IsAspNetRegistered(FrameworkVersion.Fx20));

    // These really don't exist, they are actually the .NET 2.0 version of ASP.NET.
    Console.WriteLine("ASP.NET 3.0 Registered? {0}",
        InternetInformationServicesDetection.IsAspNetRegistered(FrameworkVersion.Fx30));

    Console.WriteLine("ASP.NET 3.5 Registered? {0}",
        InternetInformationServicesDetection.IsAspNetRegistered(FrameworkVersion.Fx35));
}

Points of Interest

The public methods are simply wrappers that determine which private function should be called. These private functions, in turn, query the appropriate registry keys and process the result. However, the real work is done in the GetRegistryValue<T> function. This is a generic function that returns a boolean value indicating if the requested registry key was found and an out parameter that contains the value.

It is important to note that if the user does not have the appropriate permissions to access the registry, this function will throw an exception that will bubble up to the original caller. This was intentionally done to allow the caller the ability to take different actions based on the exception thrown.

Future Considerations

Windows XP 64-bit and Windows Vista 64-bit support. If someone wants to test this on these operating systems and let me know if it runs properly and if not what the errors are, I will correct them.

History

• 6-April-2007
• Original article
• 17-August-2007
• Updated the download to include fixes to the FrameworkVersionDetection class for the .NET Framework v3.5 Beta 2