我有一个大约有21000行的Excel文件。我将其导入到数据库中的临时表中。
现在我想对我的数据进行一些转换,然后将它们放入我的主表中。
当我在
SaveChanges()
中执行 foreach
时,出现以下错误:
Microsoft.Data.SqlClient.SqlException: 'New transaction is not allowed because there are other threads running in the session
当我在
foreach
之后使用它时,没有发生错误,并且该表只插入了 4 条记录,而不是我预期的所有 21000 条记录。
public ActionResult FeedTempdataToMainDB()
{
var L = new Leave();
// var leaves = new List<Leave>();
foreach (var item in db.TempLeaves)
{
L.Pcode = Int32.Parse(item.Cod);
var z = int.Parse(item.LT) - 1;
if (z == 0) L.LT = Leave.LeaveType.Saati;
else L.LT = Leave.LeaveType.Roozane;
var o = int.Parse(item.DLT) - 1;
if (o == 0) L.DLT = Leave.DLType.Estehghaghi;
if (o == 1) L.DLT = Leave.DLType.Estelaji;
else L.DLT = Leave.DLType.Bihoghoogh;
L.LeaveDayStart = item.LeaveDayStart.Old6digToMiladi();
L.LeaveDayEnd = item.LeaveDayEnd.Old6digToMiladi();
L.LeaveTimeStart = StringToHour(item.LeaveTimeStart);
L.LeaveTimeEnd = StringToHour(item.LeaveTimeEnd);
L.LeaveDays = int.Parse(item.LeaveDays);
L.LeaveMinuts = SaatiLengh(item.LeaveMinuts);
L.RegDate = StringToHour(item.RegTime);
L.RegDate = item.RegDate.Old6digToMiladi().Date;
L.RegistrarCode = Int32.Parse(item.RegistrarCode);
L.HijriYear = L.LeaveDayStart.GetHijriYear();
var t = IsOk(item.RegTime);
if (L.DLT == 0 && t == false || L.LT == 0)
{
L.Calculate = false;
L.IsActive = false;
}
else { L.Calculate = true; L.IsActive = true; }
db.Leaves.Add(L);
db.SaveChangesAsync();
}
//db.SaveChanges();
return RedirectToAction("index");
}
您的代码中有错误。您在循环外部声明并创建了 L。每次添加相同的 L ,只是使用不同的数据。最后,您将获得在最后一个 foreach 循环 cicle 期间创建的相同数据的列表。
试试这个:
foreach (var item in db.TempLeaves)
{
var z = int.Parse(item.LT) - 1;
var L = new Leave{
Pcode = Int32.Parse(item.Cod),
LeaveTimeStart = StringToHour(item.LeaveTimeStart),
LeaveTimeEnd = StringToHour(item.LeaveTimeEnd),
LeaveDays = int.Parse(item.LeaveDays),
LT = z == 0? Leave.LeaveType.Saati : Leave.LeaveType.Roozane
};
db.Leaves.Add(L);
}
或者这个
var leaves= new List<Leave>();
foreach (var item in db.TempLeaves)
{
var z = int.Parse(item.LT) - 1;
var L = new Leave{
Pcode = Int32.Parse(item.Cod),
LeaveTimeStart = StringToHour(item.LeaveTimeStart),
LeaveTimeEnd = StringToHour(item.LeaveTimeEnd),
LeaveDays = int.Parse(item.LeaveDays),
LT = z == 0? Leave.LeaveType.Saati : Leave.LeaveType.Roozane
};
leaves.Add(L);
}
if(leaves.Count>0)
{
db.Leaves.AddRange(leaves);
db.SaveChanges();
}
如果你想使用异步保存,你必须首先进行异步操作。
每次 foreach 执行 savechnages 时,都会有一个您无法控制的线程。由于实体框架正在管理 savechanges 功能。您必须在 foreach 之后执行 savechnages 或使用异步函数。
这是异步的示例:
private static async Task<Student> GetStudent()
{ 学生学生=空;
using (var context = new SchoolDBEntities())
{
Console.WriteLine("Start GetStudent...");
student = await (context.Students.Where(s => s.StudentID == 1).FirstOrDefaultAsync<Student>());
Console.WriteLine("Finished GetStudent...");
}
return student;
}
*这段代码终于起作用了:
public ActionResult FeedTempdataToMainDB()
{
var leaves = new List<Leave>();
foreach (var item in db.TempLeaves)
{
var L = new Leave();
L.Pcode = Int32.Parse(item.Cod);
var z = int.Parse(item.LT) - 1;
if (z == 0) L.LT = Leave.LeaveType.Saati;
else L.LT = Leave.LeaveType.Roozane;
var o = int.Parse(item.DLT);
if (o == 0) L.DLT = Leave.DLType.Estehghaghi;
if (o == 1) L.DLT = Leave.DLType.Estelaji;
else L.DLT = Leave.DLType.Bihoghoogh;
L.LeaveDayStart = item.LeaveDayStart.Old6digToMiladi();
L.LeaveDayEnd = item.LeaveDayEnd.Old6digToMiladi();
L.LeaveTimeStart = StringToHour(item.LeaveTimeStart);
L.LeaveTimeEnd = StringToHour(item.LeaveTimeEnd);
L.LeaveDays = int.Parse(item.LeaveDays);
L.LeaveMinuts = SaatiLengh(item.LeaveMinuts);
L.RegDate = StringToHour(item.RegTime);
L.RegDate = item.RegDate.Old6digToMiladi().Date;
L.RegistrarCode = Int32.Parse(item.RegistrarCode);
L.HijriYear = L.LeaveDayStart.GetHijriYear();
var t = IsOk(item.RegTime);
if (L.DLT == 0 && t == false || L.LT == 0 && t == false)
{
L.Calculate = false;
L.IsActive = false;
}
else { L.Calculate = true; L.IsActive = true; }
leaves.Add(L);
}
if (leaves.Count > 0)
{
db.Leaves.AddRange(leaves);
db.SaveChanges();
}
return RedirectToAction("index");
}