string path = ConfigurationSettings.AppSettings["DALPath"].ToString();
            Assembly assembly = Assembly.LoadFrom(path);
            Type t = assembly.GetType(spaceName + "." + className);
            Object obj = t.InvokeMember( null,
            BindingFlags.DeclaredOnly | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.CreateInstance,
            null, null, null);
   Object varReturn = t.InvokeMember(methodName,
     BindingFlags.DeclaredOnly | BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance | BindingFlags.InvokeMethod,
        null, obj, args);
参考
参考