enumerating assemblies in GAC

If you have limited access to the server then this might work:

// List of all the different types of GAC folders for both 32bit and 64bit
// environments.
List<string> gacFolders = new List<string>() { 
    "GAC", "GAC_32", "GAC_64", "GAC_MSIL", 
    "NativeImages_v2.0.50727_32", 
    "NativeImages_v2.0.50727_64",
    "NativeImages_v4.0.30319_32",
    "NativeImages_v4.0.30319_64"
};

foreach (string folder in gacFolders)
{
    string path = Path.Combine(
       Environment.ExpandEnvironmentVariables(@"%systemroot%\assembly"), 
       folder);

    if(Directory.Exists(path))
    {
        Response.Write("<hr/>" + folder + "<hr/>");

        string[] assemblyFolders = Directory.GetDirectories(path);
        foreach (string assemblyFolder in assemblyFolders)
        {
            Response.Write(assemblyFolder + "<br/>");
        }
    }
}

It basically enumerates the raw GAC folders. It works on DiscountASP shared hosting so might work for your hosting environment.

It could be embellished by enumerating deeper into each assembly's folder to yank out the version number and public key token.

a simple method to enumerate dll files in a directory

public static string[] GetGlobalAssemblyCacheFiles(string path)
{
    List<string> files = new List<string>();

    DirectoryInfo di = new DirectoryInfo(path);

    foreach (FileInfo fi in di.GetFiles("*.dll"))
    {
        files.Add(fi.FullName);
    }

    foreach (DirectoryInfo diChild in di.GetDirectories())
    {
        var files2 = GetGlobalAssemblyCacheFiles(diChild.FullName);
        files.AddRange(files2);
    }

    return files.ToArray();
}

and you can get all files

string gacPath = Environment.GetFolderPath(System.Environment.SpecialFolder.Windows) + "\\assembly";
var files = GetGlobalAssemblyCacheFiles(gacPath);

If you need to load each assembly, You get a exception for different run-time version. For this reason you can load assembly with Assembly.ReflectionOnlyLoadFrom to load Assembly in reflection only. Then, Assembly don't load in your AppDomain and don't throw exception.