Error in executing parallel entity framework queries - asp.net-core

Question

When i try to execute two different entity framwork queries at the same time it gives me an exception given below
A second operation started on this context before a previous operation completed. Any instance members are not guaranteed to be thread safe
I know that this is because of parallel execution of the _context in multi threading. but is there any alternate way to achieve both the result parallel. Here is my code.
try
{
using (_Context)
{
List<AllotedQuotas> allotedQuotas = new List<AllotedQuotas>();
List<Quotas> quotas = new List<Quotas>();
Thread t1 = new Thread(() =>
{
AllotedQuotas ob = new AllotedQuotas(_Context);
allotedQuotas = ob.GetAllotedQuotas(pid);
});
Thread t2 = new Thread(() =>
{
quotas = _Context._quotas.ToList();
});
t1.Start();
t2.Start();
t1.Join();
t2.Join();
var QuotasList = quotas.Join(allotedQuotas, QID => QID.ID, AID => AID.Quota_ID,
(_QutasName, _Alloted) => new Quotas
{
ID = _QutasName.ID,
Quota_Name = _QutasName.Quota_Name,
Active = _QutasName.Active
}).ToList();
return QuotasList;
}
}
catch (Exception ex)
{
throw ex.InnerException ?? ex;
}

Answer 1

A second operation started on this context before a previous operation completed. Any instance members are not guaranteed to be thread safe
As the error message clearly described, your main problem is here to get conflicts between different threads. To solve this, you can use mutex or lock statement to dedicate resources for only one thread for a required time and wait other threads until the resources are free. For lock statement, you could check here. To learn about threading (basics and much more) you could check this great page.