失败System.AccessViolationException: 尝试读取或写入受保护的内存。这通常指示其他内存已损坏。

   在 System.RuntimeType.ForwardCallToInvokeMember(String memberName, BindingFlags flags, Object target, Int32[] aWrapperTypes, MessageData& msgData)

   在 SAPTableFactoryCtrl._CSAPTaFacTable.get_Cell(Int32 lRow, Object vaColumn)

   在 Timer.ZLIFNR.test() 位置 D:\定时取数程序\Timer最新的\Timer\Class\Base\ZLIFNR.cs:行号 164

                    ifunc.Call();
                    SAPTableFactoryCtrl.Tables tables1 = (SAPTableFactoryCtrl.Tables)ifunc.Tables;
                    SAPTableFactoryCtrl.Table ENQ = (SAPTableFactoryCtrl.Table)tables1.get_Item("ITOT"); //ZMM18为RFC接口的Table返回名称
                    int n = ENQ.RowCount;
                    string LIFNR,NAME1,LAND1,ORT01,REGIO,SORTL,STRAS,ADRNR,MCOD1,MCOD2,MCOD3,ANRED,BBBNR,BBSNR,BUBKZ,ERDAT,ERNAM,KTOKK;
                    string KUNNR, TELF1, TELF2, TELFX, STCEG, STKZN, DUEFL, TAXBS, UPTIM;
                    //  decimal

                    for (int i = 1; i <= n; i++)
                    {
                        strsql = "";
                        count = 0;

                        LIFNR = ENQ.get_Cell(i, "LIFNR").ToString();
                        NAME1 = ENQ.get_Cell(i, "NAME1").ToString().Trim();
                        LAND1 = ENQ.get_Cell(i, "LAND1").ToString().Trim();
                        ORT01 = ENQ.get_Cell(i, "ORT01").ToString();
                        REGIO = ENQ.get_Cell(i, "REGIO").ToString();
                        SORTL = ENQ.get_Cell(i, "SORTL").ToString();
                        STRAS = ENQ.get_Cell(i, "STRAS").ToString();
                        ADRNR = ENQ.get_Cell(i, "ADRNR").ToString();
                        MCOD1 = ENQ.get_Cell(i, "MCOD1").ToString();
                        MCOD2 = ENQ.get_Cell(i, "MCOD2").ToString();
                        MCOD3 = ENQ.get_Cell(i, "MCOD3").ToString();
                        ANRED = ENQ.get_Cell(i, "ANRED").ToString();
                        BBBNR = ENQ.get_Cell(i, "BBBNR").ToString();
                        BBSNR = ENQ.get_Cell(i, "BBSNR").ToString();   
                        BUBKZ = ENQ.get_Cell(i, "BUBKZ").ToString();
                        ERDAT = ENQ.get_Cell(i, "ERDAT").ToString();

164:行：            BUBKZ = ENQ.get_Cell(i, "BUBKZ").ToString();

怎么回事 ，手工运行没有问题， 多执行几次就出现这个问题怎么回事？

失败System.AccessViolationException: 尝试读取或写入受保护的内存。这通常指示其他内存已损坏。

   在 System.RuntimeType.ForwardCallToInvokeMember(String memberName, BindingFlags flags, Object target, Int32[] aWrapperTypes, MessageData& msgData)

   在 SAPFunctionsOCX.IFunction.Call()

   在 Timer.ZMB51.test() 位置 D:\定时取数程序\Timer最新的\Timer\Class\Base\ZMB51.cs:行号 151

同时 报的这个错        ifunc.Call();这句