How do I keep different threads to have their own variable calculations?

Question

So it takes too long, if I try to do this code in serialization. So I want to do it with threading. But I'm running into safety-problems. Here is what starts the threads:

protected void Page_LoadComplete(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        using (var finished = new CountdownEvent(1))
        {
            for (int i = 1; i <= Convert.ToInt32(ViewState["Count"]); i++)
            {
                string k = i.ToString();
                ThreadInfo threadInfo = new ThreadInfo();
                threadInfo.f = k;
                finished.AddCount(); // Indicate that there is another work item.
                ThreadPool.QueueUserWorkItem(
                   (state) =>
                   {
                       try
                       {
                           Debug.WriteLine("Thread-Start Part " + k.ToString());
                           CalcThread(threadInfo);
                       }
                       finally
                       {
                           finished.Signal(); // Signal that the work item is complete.
                       }
                   }, null);
                Thread.Sleep(300);
            }
            Debug.WriteLine("Waiting till threads are done! ");
            finished.Signal(); // Signal that queueing is complete.
            finished.Wait(); // Wait for all work items to complete.
            Debug.WriteLine("Threads have completed! ");  
    }
}

Here is one place that I believe I'm getting some unsafe conditions, and I really don't know if there is a way to solve the problems. I cannot Lock ( ... ) all the code. Because that would defeat the purpose. So a lot of the calculations happen in a sub-class. The problem, I believe is when this sub-class is called, in multiple threads... the answers I'm getting back are often the same answers.

m_calculation.StartQuotePart(runnerweight, waste, machinesize, injectioncycle, volumefactor, MOQ);

m_calculation.partCostNoShiping = m_calculation.partCostNoShiping / partquantity * (1.0 + partcommission);
m_calculation.FedExShippingCost = m_calculation.FedExShippingCost / partquantity * (1.0 + partcommission);
m_calculation.DHLShippingCost = m_calculation.DHLShippingCost / partquantity * (1.0 + partcommission);
m_calculation.UPSShippingCost = m_calculation.UPSShippingCost / partquantity * (1.0 + partcommission);
m_calculation.OceanShippingCost = m_calculation.OceanShippingCost / partquantity * (1.0 + partcommission);

m_calculation.materialcost_out = m_calculation.materialcost_out / partquantity;
m_calculation.ProcessCost_out = m_calculation.ProcessCost_out / partquantity;
m_calculation.DHLshippingcost_out = m_calculation.DHLshippingcost_out / partquantity;

I have an instance for m_calculation... in the same class that is kicking off the threads. Is there a better way to access it, that wouldn't cause the issues. Is there a better way to create the threads that would cause the variable-mis-mash? This is supposed to run during the 'Page-Load-Complete' and then wait for the threads to complete with 'Finish-Wait'

Edit: I'm updating the Load-Complete with this based on jjxtra's post...

        int count = Convert.ToInt32(ViewState["Count"]);
        var tasks = new Task[count];
        for (int i = 1; i <= count; i++)
        {
            string k = i.ToString();
            ThreadInfo threadInfo = new ThreadInfo();
            threadInfo.f = k;
            tasks[i - 1] = Task.Factory.StartNew(() =>
            {
                CalcThread(threadInfo);
            });
        }
        Task.WaitAll(tasks);

How do I keep different threads to have their own variable calculations?

Answers (1)

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