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;

        }