Get the executing assembly of a web app referencing a class library

CheckValid

private static bool CheckValid(string controller, string action)
{
    if (!controller.Contains("Controller"))
    {
        controller = controller + "Controller";
    }
    // Get assembly
    Assembly a = GetWebEntryAssembly();
    if (a != null)
    {
        // Get types
        Type[] types = a.GetTypes();
        // Get controller with this name, if it exists
        Type type = types.Where( t => t.Name == controller ).SingleOrDefault();
        // Check if controller contains action, if specified
        if (string.IsNullOrEmpty(action))
        {
            // no action specified
            return type != null ? true : false;
        }
        return (type != null && type.GetMethod(action) != null) ? true : false;
    }
    return false;
}

GetWebEntryAssembly

private static Assembly GetWebEntryAssembly()
{
   if (System.Web.HttpContext.Current == null || System.Web.HttpContext.Current.ApplicationInstance == null)
   {
       return null;
   }
   var type = System.Web.HttpContext.Current.ApplicationInstance.GetType();
   while (type != null && type.Namespace == "ASP")
   {
       type = type.BaseType;
   }
   return type == null ? null : type.Assembly;
}

notWorking01

Type[] types = System.Reflection.Assembly.GetExecutingAssembly().GetTypes();

notWorking02

Type[] types = System.Reflection.Assembly.GetEntryAssembly().GetTypes();

notWorking03

Assembly a = new StackTrace().GetFrames().Last().GetMethod().Module.Assembly;

http://jacstech.wordpress.com/2013/09/05/get-the-executing-assembly-of-a-web-app-referencing-a-class-library/