ASP.NET 应用程序 - 调试步骤答案

【问题标题】：ASP.NET application - Debugging Steps to takeASP.NET 应用程序 - 调试步骤
【发布时间】：2012-04-19 19:27:39
【问题描述】：

我开发的一个应用程序每周大约崩溃 2 次。当它崩溃时，它会关闭整个应用程序，直到应用程序池被回收。我无法在开发环境中重现错误。

下面我粘贴了导致崩溃的代码和来自应用程序事件查看器的错误消息。 导致应用程序崩溃的行以 ~~~~ 开头。该消息指出我有一个打开的 DataReader，但我检查了我的代码并且我总是关闭我的数据读取器和连接。

我不知道应该采取什么步骤来解决这个错误。任何帮助将不胜感激。谢谢！

 public bool open() {
        //-- check if connection is closed
        if (this.dbconn.State == System.Data.ConnectionState.Closed) {
            try {
                this.dbconn.Open();
            }
            catch (Exception ex) {
                this.errorCode = (int)DatabaseErrorType.DBOpenFailed;
                this.errorMessage = System.Web.HttpUtility.HtmlEncode(ex.Message);
                throw ex;
            }
        }
        return true;
    }

/// <summary> closes connection object</summary>
    public bool close() {
        if (!(this.dbconn == null)) {
            if (!(this.dbconn.State == System.Data.ConnectionState.Closed)) {
                try {
                    this.dbconn.Close();
                }
                catch (Exception ex) {
                    this.errorCode = (int)DatabaseErrorType.DBCloseFailed;
                    this.errorMessage = System.Web.HttpUtility.HtmlEncode(ex.Message);
                    return false;
                }

            }
        }
        return true;
    }
        // GET MULTI Accounts
    public List<DTO.DTOAccount> GetAccounts(DTO.DTOAccount objAcc) {
        //-- reset error variables
        resetError();

        // make sure the connection is open
        if (this.open()) {

            SqlDataReader sqlReader = null;

            try {

                SqlCommand sqlProcedure = new SqlCommand("[dbo].[sp_Select_ONECARD_ACCOUNTS]", this.dbconn);
                sqlProcedure.CommandType = System.Data.CommandType.StoredProcedure;
                sqlProcedure.Parameters.Add(new SqlParameter("@ACCOUNT"             , objAcc.AccountId));
                sqlProcedure.Parameters.Add(new SqlParameter("@UDEF_4"              , objAcc.UDEF_4));

                ~~~~sqlReader = sqlProcedure.ExecuteReader();

                List<DTO.DTOAccount> Accounts = new List<DTO.DTOAccount>();
                // iterate through all values returned
                while (sqlReader.Read()) {
                    DTO.DTOAccount tmpAccount               = new ca.eyecode.onecard.DTO.DTOAccount();
                    tmpAccount.AccountId                    = (String)sqlReader["ACCOUNT"];
                    tmpAccount.Category                     = (String)sqlReader["CATEGORY"];
                    tmpAccount.Groups                       = (String)sqlReader["GROUPS"];
                    tmpAccount.Suffix                       = (String)sqlReader["SUFFIX"];
                    tmpAccount.UDEF_1                       = ((String)sqlReader["UDEF_1"]).Trim();
                    tmpAccount.UDEF_4                       = ((String)sqlReader["UDEF_4"]).Trim();
                    tmpAccount.FirstName                    = ((String)sqlReader["FNAME"]).Trim();
                    tmpAccount.LastName                     = ((String)sqlReader["LNAME"]).Trim();
                    tmpAccount.Picture                      = (sqlReader["PICTURE"] == DBNull.Value ? String.Empty : (String)sqlReader["PICTURE"]).Trim();
                    // add account items
                    tmpAccount.AccountItems.Add (new DTO.DTOAccountItem() { Account= AccountType.ONEcardCash, Balance= Convert.ToDouble((Decimal)sqlReader["BALANCE_1"])});
                    tmpAccount.AccountItems.Add (new DTO.DTOAccountItem() { Account= AccountType.Department, Balance= Convert.ToDouble((Decimal)sqlReader["BALANCE_2"])});
                    tmpAccount.AccountItems.Add (new DTO.DTOAccountItem() { Account= AccountType.BookStore, Balance= Convert.ToDouble((Decimal)sqlReader["BALANCE_3"])});
                    tmpAccount.AccountItems.Add (new DTO.DTOAccountItem() { Account= AccountType.TechBalance, Balance= Convert.ToDouble((Decimal)sqlReader["BALANCE_4"])});
                    tmpAccount.AccountItems.Add (new DTO.DTOAccountItem() { Account= AccountType.Bonus1, Balance= Convert.ToDouble((Decimal)sqlReader["BALANCE_5"])});
                    tmpAccount.AccountItems.Add (new DTO.DTOAccountItem() { Account= AccountType.MealPlanExtra, Balance= Convert.ToDouble((Decimal)sqlReader["BALANCE_6"])});
                    tmpAccount.AccountItems.Add (new DTO.DTOAccountItem() { Account= AccountType.MealPlanDollars, Balance= Convert.ToDouble((Decimal)sqlReader["BALANCE_7"])});
                    tmpAccount.AccountItems.Add (new DTO.DTOAccountItem() { Account= AccountType.AramarkCredit, Balance= Convert.ToDouble((Decimal)sqlReader["BALANCE_8"])});
                    tmpAccount.AccountItems.Add (new DTO.DTOAccountItem() { Account= AccountType.AramarkEmployees, Balance= Convert.ToDouble((Decimal)sqlReader["BALANCE_9"])});
                    // Combine Totals to One Meal PLAN
                    tmpAccount.AccountItems[5].Balance += tmpAccount.AccountItems[6].Balance;
                    tmpAccount.AccountItems[5].Balance += tmpAccount.AccountItems[8].Balance;
                    tmpAccount.AccountItems[6].Balance = 0;
                    tmpAccount.AccountItems[8].Balance = 0;

                    Accounts.Add(tmpAccount);
                }
                return Accounts;
            }
            finally {
                try {
                if (sqlReader != null)  {
                    sqlReader.Close();
                }
                }
                catch {}
                this.close();
            }

        }
        return null;
    }

错误

 Event code: 3005 
Event message: An unhandled exception has occurred. 
Event time: 4/19/2012 11:30:39 AM 
Event time (UTC): 4/19/2012 5:30:39 PM 
Event ID: 7715c17b872240829c3dfb562268998e 
Event sequence: 1253 
Event occurrence: 1 
Event detail code: 0 

Application information: 
    Application domain: /LM/W3SVC/997719702/Root-1-129793277036652335 
    Trust level: Full 
    Application Virtual Path: / 
    Application Path: 
    Machine name: 

Process information: 
    Process ID: 820 
    Process name: w3wp.exe 
    Account name: 

Exception information: 
    Exception type: InvalidOperationException 
    Exception message: There is already an open DataReader associated with this Command which must be closed first.
   at System.Data.SqlClient.SqlInternalConnectionTds.ValidateConnectionForExecute(SqlCommand command)
   at System.Data.SqlClient.SqlCommand.ValidateCommand(String method, Boolean async)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)
   at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method)
   at System.Data.SqlClient.SqlCommand.ExecuteReader()
   at ca.eyecode.onecard.DAO.DAOAccount.GetAccounts(DTOAccount objAcc) in C:\inetpub\wwwroot\ONEcard\OneAccount\OneAccount\Models\ca.eyecode\onecard\DAO\DAOAccount.cs:line 47
   at ca.eyecode.onecard.BL.BLAccount.AccountsGet(DTOAccount objAcc) in C:\inetpub\wwwroot\ONEcard\OneAccount\OneAccount\Models\ca.eyecode\onecard\BL\BLAccount.cs:line 228
   at ca.eyecode.onecard.BL.BLAccount.AccountLogin(String CCID, String Password) in C:\inetpub\wwwroot\ONEcard\OneAccount\OneAccount\Models\ca.eyecode\onecard\BL\BLAccount.cs:line 171
   at ca.eyecode.onecard.BL.BLFacade.AccountLogin(String CCID, String Password) in C:\inetpub\wwwroot\ONEcard\OneAccount\OneAccount\Models\ca.eyecode\onecard\BL\BLFacade.cs:line 36
   at ca.eyecode.onecard.Controllers.HomeController.Index(String inpCCID, String inpPASS) in C:\inetpub\wwwroot\ONEcard\OneAccount\OneAccount\Controllers\HomeController.cs:line 77
   at lambda_method(Closure , ControllerBase , Object[] )
   at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
   at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClassd.<InvokeActionMethodWithFilters>b__a()
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList`1 filters, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
   at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)
   at System.Web.Mvc.Controller.ExecuteCore()
   at System.Web.Mvc.MvcHandler.<>c__DisplayClass8.<BeginProcessRequest>b__4()
   at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass1.<MakeVoidDelegate>b__0()
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)



Request information: 
    Request URL: 
    Request path: / 
    User host address: 
    User:  
    Is authenticated: False 
    Authentication Type:  
    Thread account name: 

Thread information: 
    Thread ID: 9 
    Thread account name:  
    Is impersonating: False 
    Stack trace:    at System.Data.SqlClient.SqlInternalConnectionTds.ValidateConnectionForExecute(SqlCommand command)
   at System.Data.SqlClient.SqlCommand.ValidateCommand(String method, Boolean async)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result)
   at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)
   at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method)
   at System.Data.SqlClient.SqlCommand.ExecuteReader()
   at ca.eyecode.onecard.DAO.DAOAccount.GetAccounts(DTOAccount objAcc) in C:\inetpub\wwwroot\ONEcard\OneAccount\OneAccount\Models\ca.eyecode\onecard\DAO\DAOAccount.cs:line 47
   at ca.eyecode.onecard.BL.BLAccount.AccountsGet(DTOAccount objAcc) in C:\inetpub\wwwroot\ONEcard\OneAccount\OneAccount\Models\ca.eyecode\onecard\BL\BLAccount.cs:line 228
   at ca.eyecode.onecard.BL.BLAccount.AccountLogin(String CCID, String Password) in C:\inetpub\wwwroot\ONEcard\OneAccount\OneAccount\Models\ca.eyecode\onecard\BL\BLAccount.cs:line 171
   at ca.eyecode.onecard.BL.BLFacade.AccountLogin(String CCID, String Password) in C:\inetpub\wwwroot\ONEcard\OneAccount\OneAccount\Models\ca.eyecode\onecard\BL\BLFacade.cs:line 36
   at ca.eyecode.onecard.Controllers.HomeController.Index(String inpCCID, String inpPASS) in C:\inetpub\wwwroot\ONEcard\OneAccount\OneAccount\Controllers\HomeController.cs:line 77
   at lambda_method(Closure , ControllerBase , Object[] )
   at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary`2 parameters)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
   at System.Web.Mvc.ControllerActionInvoker.<>c__DisplayClassd.<InvokeActionMethodWithFilters>b__a()
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func`1 continuation)
   at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList`1 filters, ActionDescriptor actionDescriptor, IDictionary`2 parameters)
   at System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName)
   at System.Web.Mvc.Controller.ExecuteCore()
   at System.Web.Mvc.MvcHandler.<>c__DisplayClass8.<BeginProcessRequest>b__4()
   at System.Web.Mvc.Async.AsyncResultWrapper.<>c__DisplayClass1.<MakeVoidDelegate>b__0()
   at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

【问题讨论】：

为什么没有发现异常？
如果这会导致整个网站崩溃，我至少会尝试吃掉异常并将用户发送到错误页面，看看是否可以防止网站崩溃。然后我会专注于根本问题。
嗨，我没有发现错误，但我在 finally 块中关闭了阅读器
Jason 关于发回错误的观点很好，但这并不能解释为什么它会导致整个网站崩溃。
问题是我的代码中有一个 try finally 块。这是一个问题，因为在某些情况下 finally 不会被调用。为了确保每次都执行 finally 块，您不能省略 catch 块。 msdn.microsoft.com/en-us/library/zwc8s4fz(v=vs.100).aspx

标签： asp.net debugging iis-6 visual-studio-debugging

【解决方案1】：

当然，您可以在 SqlDataReader 周围使用 using 语句。对其他元素执行相同操作。这样您就可以确定它们总是被丢弃和关闭。

除此之外，请确保您没有嵌套 SqlDataReaders。尽快关闭它们，并按顺序进行数据访问。这应该可以解决问题。

【讨论】：

【解决方案2】：

问题是我的代码中有一个 try finally 块。在已处理的异常中，保证运行关联的 finally 块。但是，如果异常未处理，finally 块的执行取决于异常展开操作的触发方式。反过来，这取决于您的计算机的设置方式。

为了确保每次都执行 finally 块，您不能省略 catch 块。 http://msdn.microsoft.com/en-us/library/zwc8s4fz(v=vs.100).aspx

【讨论】：

【解决方案3】：

除非您真的需要其他地方的连接对象，否则我会将方法重构为：

public List<DTO.DTOAccount> GetAccounts(DTO.DTOAccount objAcc)
{
    //-- reset error variables
    resetError();

    List<DTO.DTOAccount> Accounts = new List<DTO.DTOAccount>();

    try
    {
        using (SqlConnection dbconn = new SqlConnection("your-connection-string"))
        {
            using (SqlCommand sqlProcedure = new SqlCommand("[dbo].[sp_Select_ONECARD_ACCOUNTS]", dbconn))
            {
                sqlProcedure.CommandType = System.Data.CommandType.StoredProcedure;
                sqlProcedure.Parameters.Add(new SqlParameter("@ACCOUNT", objAcc.AccountId));
                sqlProcedure.Parameters.Add(new SqlParameter("@UDEF_4", objAcc.UDEF_4));
                dbconn.Open();
                using (SqlDataReader sqlReader = sqlProcedure.ExecuteReader())
                {
                    while (sqlReader.Read())
                    {
                        DTO.DTOAccount tmpAccount = new ca.eyecode.onecard.DTO.DTOAccount();
                        tmpAccount.AccountId = (String)sqlReader["ACCOUNT"];
                        tmpAccount.Category = (String)sqlReader["CATEGORY"];
                        tmpAccount.Groups = (String)sqlReader["GROUPS"];
                        tmpAccount.Suffix = (String)sqlReader["SUFFIX"];
                        tmpAccount.UDEF_1 = ((String)sqlReader["UDEF_1"]).Trim();
                        tmpAccount.UDEF_4 = ((String)sqlReader["UDEF_4"]).Trim();
                        tmpAccount.FirstName = ((String)sqlReader["FNAME"]).Trim();
                        tmpAccount.LastName = ((String)sqlReader["LNAME"]).Trim();
                        tmpAccount.Picture = (sqlReader["PICTURE"] == DBNull.Value ? String.Empty : (String)sqlReader["PICTURE"]).Trim();
                        // add account items
                        tmpAccount.AccountItems.Add(new DTO.DTOAccountItem() { Account = AccountType.ONEcardCash, Balance = Convert.ToDouble((Decimal)sqlReader["BALANCE_1"]) });
                        tmpAccount.AccountItems.Add(new DTO.DTOAccountItem() { Account = AccountType.Department, Balance = Convert.ToDouble((Decimal)sqlReader["BALANCE_2"]) });
                        tmpAccount.AccountItems.Add(new DTO.DTOAccountItem() { Account = AccountType.BookStore, Balance = Convert.ToDouble((Decimal)sqlReader["BALANCE_3"]) });
                        tmpAccount.AccountItems.Add(new DTO.DTOAccountItem() { Account = AccountType.TechBalance, Balance = Convert.ToDouble((Decimal)sqlReader["BALANCE_4"]) });
                        tmpAccount.AccountItems.Add(new DTO.DTOAccountItem() { Account = AccountType.Bonus1, Balance = Convert.ToDouble((Decimal)sqlReader["BALANCE_5"]) });
                        tmpAccount.AccountItems.Add(new DTO.DTOAccountItem() { Account = AccountType.MealPlanExtra, Balance = Convert.ToDouble((Decimal)sqlReader["BALANCE_6"]) });
                        tmpAccount.AccountItems.Add(new DTO.DTOAccountItem() { Account = AccountType.MealPlanDollars, Balance = Convert.ToDouble((Decimal)sqlReader["BALANCE_7"]) });
                        tmpAccount.AccountItems.Add(new DTO.DTOAccountItem() { Account = AccountType.AramarkCredit, Balance = Convert.ToDouble((Decimal)sqlReader["BALANCE_8"]) });
                        tmpAccount.AccountItems.Add(new DTO.DTOAccountItem() { Account = AccountType.AramarkEmployees, Balance = Convert.ToDouble((Decimal)sqlReader["BALANCE_9"]) });
                        // Combine Totals to One Meal PLAN
                        tmpAccount.AccountItems[5].Balance += tmpAccount.AccountItems[6].Balance;
                        tmpAccount.AccountItems[5].Balance += tmpAccount.AccountItems[8].Balance;
                        tmpAccount.AccountItems[6].Balance = 0;
                        tmpAccount.AccountItems[8].Balance = 0;

                        Accounts.Add(tmpAccount);
                    }
                }
            }
        }
    }
    catch
    {
        // do some error handling.
    }

    return Accounts;
}

【讨论】：