Infopath FileQueryConnection.Execute（XpathNavigator）引发System.Net.WebException：尝试读取或写入受保护的内存

Question

我在启用浏览器的infopath表单2007的字段更改事件中包含此代码-

 try
        {

        XmlDocument outputFile = new XmlDocument();
FileQueryConnection con = (FileQueryConnection)DataConnections["connection1"];
con.FileLocation = @"http://server_name/_vti_bin/owssvr.dll"
         + "?Cmd=Display&List={List_ID}"
         + "&XMLDATA=TRUE&View={View_ID}&Query=*"
            + "&FilterField1=Country_x0020_Name&FilterValue1="
            + country.Replace("&","%26");
            outputFile.LoadXml("<?xml version=\"1.0\" encoding=\"utf-8\" ?><outputRoot></outputRoot>");

            XmlNamespaceManager outputFileNamespaceManager = new XmlNamespaceManager(outputFile.NameTable);

            // XmlDocument output file created above.
            XPathNavigator outputFileNavigator = outputFile.CreateNavigator();
            XPathNavigator outputRootNavigator = 
            outputFileNavigator.SelectSingleNode("/outputRoot",outputFileNamespaceManager);
            con.Execute(outputRootNavigator);
            File.AppendAllText(@"E:\log.txt", outputRootNavigator.ToString());
        }
        catch (Exception exp)
        {
            File.AppendAllText(@"E:\exp.txt", exp.ToString());
        }

我得到这个例外-

System.Net.WebException: Attempted to read or write protected memory. This is often an indication that other memory is corrupt.at Microsoft.Office.InfoPath.Internal.MomExceptionHelper.ExecuteDataConnectionAction(OMCall d) at Microsoft.Office.InfoPath.Internal.FileQueryConnectionHost.Execute(XPathNavigator output) at cascadeTemplate.FormCode.field1_Changed(Object sender, XmlEventArgs e)

为什么会引发这样的异常？ 我在代码中缺少什么吗？

谢谢您的帮助！

Answer 1

它最有可能是由FileQueryConnection引起的。 由于从未使用con变量，因此请删除以下行：

     FileQueryConnection con = (FileQueryConnection)DataConnections["connection1"];
     con.FileLocation = ...

Answer 2

con.Execute（outputRootNavigator）; 写入日志文件之前，应在此处关闭连接“ con”。 File.AppendAllText（@“ E：\\ log.txt”，outputRootNavigator.ToString（））;