Avoiding Stack Overflow Exception

Question

I am stuck with a stack overflow exception in this section of code, it is obviously occurring because the Customer object calls a list of CustomerBackgroundLevel objects, each one of which creates a new customer object. I am trying to find a way around the issue, any help would be appreciated..

Customer Constructor -

public CustomerVO(Customer item)
    {
        CustomerID = item.CustomerID;
        CustomerName = item.CustomerName;
        ECNNumber = item.ECNNumber;

        CustomerBackgroundLevels = item.CustomerBackgroundLevels.Select(c => new CustomerBackgroundLevelVO(c)).ToList();
    }

Customer Background Level Constructor -

        public CustomerBackgroundLevelVO(CustomerBackgroundLevel item)
    {
        CustomerBackgroundLevelID = item.CustomerBackgroundLevelID;
        CustomerID = item.CustomerID;
        BackgroundLevelID = item.BackgroundLevelID;
        StartDate = item.StartDate;
        EndDate = item.EndDate;
        Customer = new CustomerVO(item.Customer);
        BackgroundLevel = new BackgroundLevelVO(item.BackgroundLevel);
    }

Customer Get Method -

        public CustomerVO GetByID(int id)
    {
        var item = repository.AsQueryable().Where(x => x.CustomerID == id).FirstOrDefault();
        if (item == null)
            return null;

        return new CustomerVO(item);
    }

As a solution, perhaps add a constructor overload for CustomerBackgroundLevelVO that takes a CustomerVO. Then you can just directly assign it to CustomerBackgroundLevelVO.Customer rather than instantiating a new one. Your Linq call in the CustomerVO constructor would then look like: CustomerBackgroundLevels = item.CustomerBackgroundLevels.Select(c => new CustomerBackgroundLevelVO(c, this)).ToList() which will avoid the infinite loop. This only makes sense though if you A) want to reuse the same CustomerVO object, and B) don't mind passing a not fully initialized object. — Chris Sinclair
– Chris Sinclair, Commented Mar 26, 2013 at 13:13
Or better yet, ditch all this wiring/sub-object construction in their constructors and delegate it out to a specific Factory or Builder object to create/wire these objects for you and avoid all the nested/recursive interdependencies altogether. — Chris Sinclair
– Chris Sinclair, Commented Mar 26, 2013 at 13:14

j__m · Accepted Answer · 2013-03-26 13:11:05Z

2

Yeah, as you've stated creating new objects in a loop like that is gonna lead to nothing good.

Instead of creating all these wrapper objects in your constructors, why don't you wrap them on demand? That is, when you execute some code that needs a CustomerVO object, create the CustomerVO object within that function and then let it go out of scope when the function ends.

answered Mar 26, 2013 at 13:11

j__m

9,7101 gold badge35 silver badges59 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

Peter · Accepted Answer · 2013-03-26 13:08:14Z

1

You can solve your loop like this:

public CustomerVO(Customer item)
{
    CustomerID = item.CustomerID;
    CustomerName = item.CustomerName;
    ECNNumber = item.ECNNumber;

    **CustomerBackgroundLevels = item.CustomerBackgroundLevels.Select(c => new CustomerBackgroundLevelVO(c,this)).ToList();
}

**public CustomerBackgroundLevelVO(CustomerBackgroundLevel item, CustomerVO vocustomer)
{
    CustomerBackgroundLevelID = item.CustomerBackgroundLevelID;
    CustomerID = item.CustomerID;
    BackgroundLevelID = item.BackgroundLevelID;
    StartDate = item.StartDate;
    EndDate = item.EndDate;
    **Customer = vocustomer;
    BackgroundLevel = new BackgroundLevelVO(item.BackgroundLevel);
}

answered Mar 26, 2013 at 13:08

Peter

28k8 gold badges69 silver badges85 bronze badges

1 Comment

user1948635 Over a year ago

Thanks for this, works very nicely. Probably going to have to re-consider this approach now though, due to the initial load speed :(

Caleb Keith · Accepted Answer · 2013-03-26 13:11:48Z

0

Is that a copy constructor? If so, you need to create a custom constructor for copying the item rather than using it in both scenarios where you new up an object and copy it.

return new CustomerVO(item);

The above is unnecessary and the problem line is:

Customer = new CustomerVO(item.Customer);

Change the above line to this:

Customer = item.Customer;

Unless you are having reference problems, which means you need to design a new constructor.

And if the item.Customer object is not a CustomerVO object, then you will need to pass the reference of the current CustomerVO object into the constructor of the CustomerBackgroundLevelVO.

answered Mar 26, 2013 at 13:11

Caleb Keith

8264 silver badges10 bronze badges

Collectives™ on Stack Overflow

Avoiding Stack Overflow Exception

3 Answers 3

Comments

1 Comment

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

Comments

1 Comment

Comments

Your Answer

Sign up or log in

Post as a guest

Related