linq查询中未处理的异常

Question

说明：由于未处理的异常，进程已终止。 异常信息信息：System.InvalidOperationException堆栈：在 System.Data.Linq.Table 1[[System.__Canon, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089]].CheckReadOnly()
at System.Data.Linq.Table 1 [[系统_ 佳能，mscorlib程序， 版本= 4.0.0.0，文化=中性 公钥= b77a5c561934e089]] DeleteOnSubmit（。系统。 _Canon）在 ReportSender.EmailReportApp.Execute（）在 System.Threading.ThreadHelper.ThreadStart_Context（System.Object的）在 System.Threading.ExecutionContext.Run（System.Threading.ExecutionContext， System.Threading.ContextCallback ，System.Object，Boolean） System.Threading.ExecutionContext.Run（System.Threading.ExecutionContext， System.Threading.ContextCallback，System.Object）at System.Threading.ThreadHelper.ThreadStart（）

我正在试图在下面的查询删除记录时，上面的错误： 这个错误是什么意思准确，我该如何解决？

private void Execute() 
{ 
    try 
    { 
     // Check for a new record 
     DataClasses1DataContext dc = new DataClasses1DataContext(); 

     foreach (var item in dc.reportsSent1s) 
     { 
      string matchedCaseNumber = item.CaseNumberKey; 

      (new MyReportRenderer()).RenderTest(matchedCaseNumber); 

      dc.reportsSent1s.DeleteOnSubmit(item); 
      dc.SubmitChanges(); 
     } 
    } 
    catch (ThreadAbortException ex) 
    { 
     _log.WriteEntry(ex.StackTrace.ToString()); 
    } 
} 

的其余代码如下：

public class MyReportRenderer 
{ 
    private rs2005.ReportingService2005 rs; 
    private rs2005Execution.ReportExecutionService rsExec; 

    public void RenderTest(String matchedCaseNumber) 
    { 
     string HistoryID = null; 
     string deviceInfo = null; 
     string encoding = String.Empty; 
     string mimeType = String.Empty; 
     string extension = String.Empty; 
     rs2005Execution.Warning[] warnings = null; 
     string[] streamIDs = null; 

     rs = new rs2005.ReportingService2005(); 
     rsExec = new rs2005Execution.ReportExecutionService(); 
     rs.Credentials = System.Net.CredentialCache.DefaultCredentials; 
     rsExec.Credentials = System.Net.CredentialCache.DefaultCredentials; 
     rs.Url = "http://***.**.***.**/ReportServer_DEVELOPMENT/ReportService2005.asmx"; 
     rsExec.Url = "http://***.**.***.**/ReportServer_DEVELOPMENT/ReportExecution2005.asmx"; 

     try 
     { 
      // Load the selected report. 
      rsExec.LoadReport("/LawDept/LawDeptTIC", HistoryID); 

      // Set the parameters for the report needed. 

      rs2005Execution.ParameterValue[] parameters = new rs2005Execution.ParameterValue[1]; 
      parameters[0] = new rs2005Execution.ParameterValue(); 
      parameters[0].Name = "CaseNumberKey"; 
      parameters[0].Value = matchedCaseNumber; 

      rsExec.SetExecutionParameters(parameters, "en-us"); 

      // get pdf of report 
      Byte[] results = rsExec.Render("PDF", deviceInfo, 
      out extension, out encoding, 
      out mimeType, out warnings, out streamIDs); 

      //pass paramaters for email 
      DataClasses1DataContext db = new DataClasses1DataContext(); 

      var matchedBRT = (from c in db.GetTable<vw_ProductClientInfo>() 
           where c.CaseNumberKey == matchedCaseNumber 
           select c.BRTNumber).SingleOrDefault(); 

      var matchedAdd = (from c in db.GetTable<vw_ProductClientInfo>() 
           where c.CaseNumberKey == matchedCaseNumber 
           select c.Premises).SingleOrDefault(); 

      //send email with attachment 
      MailMessage message = new MailMessage("Rts@acmets.com", "gge.grer@gmail.com", "Report for BRT # " + matchedAdd, "Attached if the Tax Information Certificate for the aboved captioned BRT Number"); 
      MailAddress copy = new MailAddress("cts@gmail.com"); 
      message.CC.Add(copy); 
      SmtpClient emailClient = new SmtpClient("***.**.***.**"); 
      message.Attachments.Add(new Attachment(new MemoryStream(results), String.Format("{0}" + matchedBRT + ".pdf", "BRT"))); 
      emailClient.Send(message); 
     } 
     catch (Exception ex) 
     { 
      Console.WriteLine(ex.Message); 
     } 
    } 
} 

Answer 1

看起来像LINQ to SQL是检查如果表是只读或没有，被挑剔的表是只读的，抛出的结果（不能从只读表中删除）。因此，您需要调查为什么LINQ to SQL认为该表是只读的。你在桌上有主键吗？我知道没有一个是LINQ to SQL认为表是只读的常见原因（LINQ to SQL需要它为identity map）。如果这不起作用，George Johnston的suggestion尝试将呼叫移至SubmitChanges以外的循环是很好的;在桌面上获得一个枚举器可能会在上下文中激活只读锁，这就是为什么CheckReadOnly在调用提交失败。