How to Return Thread result

Question

How would I go about returning the "var T" like the "var result" in the example below(code comments) in the new Thread that I created?

public QuoteResult GetQuote(QuoteData Data)
{
    using (TruckDb db = new TruckDb())
    {
        const int stackSize = 8000000;
        var T = new Thread(() => CalculateRates(db, Data), stackSize);
        T.Priority = ThreadPriority.Highest;
        T.Start();
        T.Join();

        //var result = CalculateRates(db, Data);
        //return result; //Example of how I want it in the new thread created above
    }
}

My CalculateRates method coding:

public QuoteResult CalculateRates(TruckDb db, QuoteData data)
{
    var result = new QuoteResult
    {
        Successful = false,
        Data = data
    };

    List<QuoteItemSectionGroup> quoteItems = new List<QuoteItemSectionGroup>();

    var quoteItem = new QuoteItem
    {
        ChassisModel = db.ChassisModel.Find(data.ChassisId),
        ChassisManufacturer = db.ChassisManufacturer.Find(data.ChassisManufacturerId),
        BodyType = db.BodyTypes.Find(data.BodyTypeId),
        //...10 lines more
    };

    //...unnecessary to see codes and calculations...

    result.QuoteItem = quoteItem;
    result.Successful = true;
    return result;
}

I just need to run my CalculateRates method in a new thread to increase the stack size. If you need any more code or information, please don't hesitate to ask. Thank you!

Answer 1

The most straightforward way to do this is

QuoteResult qr = null;
var T = new Thread(() => qr = CalculateRates(db, Data), stackSize);
T.Priority = ThreadPriority.Highest;
T.Start();
T.Join();
return qr;

Alternatively, another way to do this, in this context, is to use an out parameter instead of a function return value. This is of particular use if you need to return more than one value.

public void CalculateRates(TruckDb db, QuoteData data, out QuoteResult qrResult)
{
    qrResult= new QuoteResult
    {
        Successful = false,
        Data = data
    };    

    //...unnecessary to see codes and calculations...

    qrResult.QuoteItem = quoteItem;
    qrResult.Successful = true;        
}

Then call as :

 QuoteResult qr = null;
 var T = new Thread(() => CalculateRates(db, Data, out qr), stackSize);
 T.Priority = ThreadPriority.Highest;
 T.Start();
 T.Join();
 return qr;

In both cases the null initialization is necessary because the compiler cannot see across the thread boundary to determine that a value has actually been assigned. Without the .Join call, for example, it's quite likely that a value would not yet have been assigned so you have to be explicit.