此方法 - doDayBegin(item.BranchId)
需要很长时间才能执行。所以我使用 Parallel.ForEach
并行执行它。当我使用普通的 foreach
循环时它工作正常但是当我使用 Parallel.ForEach
时它显示这个错误
对象引用未设置到对象的实例。
public ActionResult Edit([DataSourceRequest] DataSourceRequest request)
{
try
{
JavaScriptSerializer js = new JavaScriptSerializer();
List<DB0010020Vm> _listDB0010020Vm = new List<DB0010020Vm>();
string dataDB0010020vm = Request.Form["griddetailsvm"];
if (!string.IsNullOrEmpty(dataDB0010020vm))
{
_listDB0010020Vm = js.Deserialize<List<DB0010020Vm>>(dataDB0010020vm).
Where(d => d.IsValid == "YES").ToList();
}
DateTime start = DateTime.UtcNow;
Parallel.ForEach(_listDB0010020Vm, item =>
{
doDayBegin(item.BranchId);
});
DateTime end = DateTime.UtcNow;
TimeSpan duration = end - start;
return Json(new
{
success = true,
message = "Day Begin Process Completed Successfully!" + duration
});
}
catch (Exception e)
{
return Json(new
{
success = false,
message = e.Message
});
}
}
public void doDayBegin(int BranchId)
{
var httpContext = System.Web.HttpContext.Current;
IDB0010020Repository _idDB0010020Repository = new DB0010020Repository();
IDB0010044Repository _idDB0010044Repository = new DB0010044Repository();
EBS.DAL.Model.DB0010020 branchDetails = _idDB0010020Repository.FindOne(d => d.BranchId == BranchId);
if (branchDetails == null)
{
ModelState.AddModelError("", "Branch not found!");
}
else
{
try
{
DateTime LastOpenDate = DateTime.ParseExact(Request.Form["LastOpenDate"].ToString(), "dd/MM/yyyy", CultureInfo.InvariantCulture);
// branchDetails.LastOpenDate = LastOpenDate;
// branchDetails.LastOpenDate = Convert.ToDateTime(Request.Form["LastOpenDate"].ToString());
}
catch (Exception e)
{
// branchDetails.LastOpenDate = Convert.ToDateTime("2014-07-25 00:00:00.000");
}
OperationStatus status = _idDB0010020Repository.UpdateAndSave(branchDetails);
if (status != null && !status.Status)
ModelState.AddModelError("Updation failed", status.ExceptionMessage);
}
EBS.DAL.Model.DB0010044 dayBegin = new DB0010044();
dayBegin.BankId = 1;
dayBegin.BranchId = BranchId;
dayBegin.DayBeginFlag = 1;
//added d
DateTime DayDate = DateTime.ParseExact(Request.Form["LastOpenDate"].ToString(), "dd/MM/yyyy", CultureInfo.InvariantCulture);
dayBegin.DayDate = DayDate;
//added d
// dayBegin.DayDate = Convert.ToDateTime(Request.Form["LastOpenDate"]);
dayBegin.DayEndFlag = 0;
dayBegin.DayEndStage = 1;
dayBegin.DayReopenFlag = 0;
OperationStatus status2 = _idDB0010044Repository.AddAndSave(dayBegin);
if (status2 != null && !status2.Status)
ModelState.AddModelError("Updation failed", status2.ExceptionMessage);
else
{
CreateInwardSessionsForBranch(BranchId);
CreateOutwardSessionsForBranch(BranchId);
}
}
这是错误
会出现什么问题?为什么我的 session 为空。有什么办法可以解决
最佳答案
HttpContext.Current
是按线程设置的。因此,当您使用 Parallel.ForEach
启动更多线程时,您的新线程无法以这种方式访问它。解决方案是将所需的值作为参数一直传递,而不是依赖存储库中的 HttpContext.Current
。
SO 上有几个来源已经涵盖了这个问题。
The cross-thread usage of "HttpContext.Current" property and related things
关于c# - Parallel.ForEach 错误 HttpContext.Current,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/26710980/