returns a comma delimited list of available .net frameworks

GetAvailableFrameworks

// need this to be able to run in .net 2.0.  The result of this is to be sent up
// to the server by the client so that we can determine what versions of the
// .net framework that our users have installed
private string GetAvailableFrameworks()
{
    string frameworkRegistryPath = @"Software\Microsoft\.netframework";
    List<string> versions = new List<string>();
    RegistryKey key = Registry.LocalMachine.OpenSubKey(frameworkRegistryPath);
    if (key == null)
    {
        return String.Format("{0} not found.", frameworkRegistryPath);
    }
    foreach (var subkey in key.GetSubKeyNames())
    {
        if (subkey.StartsWith("v"))
        {
            versions.Add(subkey.Substring(1));
        }
    }
    return String.Join(",", versions.ToArray());
}