Revision: Get the Value of a Control Without an Instance of the Control

On an earlier post, I provided code that would retrieve the value of a control from the HTTP post without the need for an instance of the control.  With good feedback, I made some modifications as follows:

public static string GetControlValueFromRequest(string controlId)
{
    if (controlId == null)
        throw new ArgumentNullException("controlId");
    string requestValue = null;
    HttpRequest req = HttpContext.Current.Request;
    string eventTarget = req.Form["__EVENTTARGET"] ?? string.Empty;
    if (eventTarget.Equals(controlId, StringComparison.InvariantCultureIgnoreCase))
    {
        requestValue = req.Form["__EVENTARGUMENT"];
    }
    if (string.IsNullOrEmpty(requestValue))
    {
        foreach (string id in req.Form.AllKeys)
        {
            if (controlId.Equals(GetFriendlyControlId(id), StringComparison.InvariantCultureIgnoreCase))
            {
                requestValue = req[id];
                break;
            }
        }
    }
    return requestValue;
}