protected static object MObjLock = new object();//同步锁
        public string GetData(int mId)
        {
            Monitor.Enter(MObjLock);//lock
            string data = string.Empty;
            try
            {
                 //你的代码                

            }
            catch (Exception err)
            {
                Log4NetHelper.WriteError(err);
            }
            finally
            {
                Monitor.Exit(MObjLock);//unlock
            }
            return data;
        }