Question

我收到一个并非经常发生的错误，但是客户已经看到并想要修复它。

基本上，它是 IndexOutOfRangeException 异常，但奇怪的是跟踪指向 System.Web.HttpContext.Current 。怎么可能？

失败的行是这样的：

     在   System.Collections.ArrayList.Add（Object value）at   System.Collections.Specialized.NameObjectCollectionBase.BaseAdd（字符串   名称，对象值）at   System.Web.SessionState.SessionStateItemCollection.set_Item（字符串   名称，对象值）at   WebStateManager.set_Item（String key，Object value）   在   \ WebStateManager.cs：行   在UIStateManager.get_BookingParameters（）中的53   WS \ App_Code文件\管理\ UIStateManager.cs：行   2746
      指数超出了界限   数组。

System.Web.HttpContext context = System.Web.HttpContext.Current;

如果它是一个数组，我可以做计数和其他检查，但除了try-catch之外，我会在这里做什么样的检查？ enter link description here

public class Example
{
   public static void Main()
   {
      int[] values1 = { 3, 6, 9, 12, 15, 18, 21 };
      int[] values2 = new int[6];

      // Assign last element of the array to the new array.
      values2[values1.Length - 1] = values1[values1.Length - 1];
   }
}
// The example displays the following output:
//       Unhandled Exception: 
//       System.IndexOutOfRangeException: 
//       Index was outside the bounds of the array.
//       at Example.Main()

我的项目代码

public override object this[string key]
        {
            get
            {
                if (Helpers.CommonFunctions.IsHttpSessionNull)
                { return null; }

                return HttpContext.Current.Session[key + Helpers.CommonFunctions.GetAppDomainMultiplexer()];
            }
            set
            {
                if (Helpers.CommonFunctions.IsHttpSessionNull)
                { return; }

                if (value == null)
                {
                    try
                    {
                        if (HttpContext.Current.Session[key + Helpers.CommonFunctions.GetAppDomainMultiplexer()] != null)
                        {
                            HttpContext.Current.Session.Remove(key + Helpers.CommonFunctions.GetAppDomainMultiplexer());
                        }
                    }
                    catch
                    {
                    }
                }
                else
                {
                        HttpContext.Current.Session[key + Helpers.CommonFunctions.GetAppDomainMultiplexer()] = value;

                }
            }
        }

故障堆栈跟踪如下;

0:072> !clrstack
    OS Thread Id: 0x31ec (72)
            Child SP               IP Call Site
    000000aea766d968 000007f9736a4650 [HelperMethodFrame: 000000aea766d968] 
    000000aea766da50 000007f9674e0e5a System.Collections.ArrayList.Add(System.Object)
    000000aea766da90 000007f966655292 System.Collections.Specialized.NameObjectCollectionBase.BaseAdd(System.String, System.Object)
    000000aea766dae0 000007f9650ac4c9 System.Web.SessionState.SessionStateItemCollection.set_Item(System.String, System.Object)
    000000aea766db20 000007f90ed89ce9 UTL.WebStateManager.set_Item(System.String, System.Object)
    000000aea766dbf0 000007f90f29370c WebStateManagerHelper.get_OriginalPNR()
    000000aea766dc80 000007f90f29242d QueryDynamicLoggingComponent.LogTransaction(System.String, System.String)
    000000aea766e110 000007f90f2917e3 WSHelper.Log(System.String, System.String, Boolean, System.String)
    000000aea766e160 000007f90f28fd17 WSHelper.GetResponse(System.String, SecurityInfo, System.String, System.String, System.String ByRef, System.String, System.String)
    000000aea766e5d0 000007f90f29eae6 WSHelper.SendQuery(System.String, SecurityInfo, System.String)
    000000aea766e7f0 000007f90f29e7f8 WSHelper.SendQuery(SecurityInfo, System.String)
    000000aea766e840 000007f90f29e4af APIWSPool.SendAndReceiveQueryToString(Agency, System.String, Token, Boolean)
    000000aea766e940 000007f90f29e374 APIWSPool.SendAndReceiveQuery(Agency, Token, Boolean)
    000000aea766e9b0 000007f90f6168f4 FlightBookingManager.SearchFlightForMPSearchedFlightRecommendations1(Agency, FlightFareDrivenSearchInfo, Boolean)
    000000aea766eb80 000007f90f615ec1 ApiFlightBookingProvider.SearchFlightForMPSearchedFlightRecommendations1(Agency, FlightFareDrivenSearchInfo, Boolean)
    000000aea766ebe0 000007f90f6158f2 APICOM.Threading.OWCOutboundSearchThread.Work()
    000000aea766edb0 000007f9674e2d45 System.Threading.ExecutionContext.RunInternal(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
    000000aea766ef10 000007f9674e2ab9 System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object, Boolean)
    000000aea766ef40 000007f9674e2a97 System.Threading.ExecutionContext.Run(System.Threading.ExecutionContext, System.Threading.ContextCallback, System.Object)
    000000aea766ef90 000007f9674fa161 System.Threading.ThreadHelper.ThreadStart()
    000000aea766f2a8 000007f96e0eab53 [GCFrame: 000000aea766f2a8] 
    000000aea766f5f8 000007f96e0eab53 [DebuggerU2MCatchHandlerFrame: 000000aea766f5f8] 
    000000aea766f788 000007f96e0eab53 [ContextTransitionFrame: 000000aea766f788] 
    000000aea766f9a8 000007f96e0eab53 [DebuggerU2MCatchHandlerFrame: 000000aea766f9a8]

Answer 1

SessionStateItemCollection不是线程安全的（请参阅https://msdn.microsoft.com/en-us/library/system.web.sessionstate.sessionstateitemcollection(v=vs.110).aspx），并且您可能有多个线程同时从会话状态写入/读取。

您需要找到访问HttpContext.Session或Page.Session的代码，并确保代码未在后台线程中运行。

请参阅https://msdn.microsoft.com/en-us/library/system.indexoutofrangeexception(v=vs.110).aspx - （搜索“违反线程安全”）

下面是一些使用锁定试图避免此问题的示例代码。这段代码非常快速而且很脏。我不推荐它。但是，如果不重新构建您的系统，那可能是值得的。如果您使用此技术，则必须将其置于每次使用Session。

    public override object this[string key]
    {
        get
        {
            if (Helpers.CommonFunctions.IsHttpSessionNull)
            { return null; }

            lock (HttpContext.Current.Session)
            { 
                return HttpContext.Current.Session[key + Helpers.CommonFunctions.GetAppDomainMultiplexer()];
            }
        }
        set
        {
            if (Helpers.CommonFunctions.IsHttpSessionNull)
            { return; }

            lock (HttpContext.Current.Session)
            {
                if (value == null)
                {
                    try
                    {
                        if (HttpContext.Current.Session[key + Helpers.CommonFunctions.GetAppDomainMultiplexer()] != null)
                        {
                            HttpContext.Current.Session.Remove(key + Helpers.CommonFunctions.GetAppDomainMultiplexer());
                        }
                    }
                    catch
                    {
                    }
                }
                else
                {
                    HttpContext.Current.Session[key + Helpers.CommonFunctions.GetAppDomainMultiplexer()] = value;

                }
            }
        }

在什么情况下C＃ASP.NET HttpContext.Current.Session抛出，IndexOutOfRangeException？

1 个答案: