Modify instance variable used by multiple Tasks

I need some help with handling Tasks. I have an XML String which is deserialized into a class. The class itself contains a property, eg rssProvider which is set to an unique value like MSN or YAHOO. However there can be multiple values delimited with an , in this field.

I am using this deserialized class instance in multiple Tasks. However the function which gets called in this task can only work with one rssProvider value, so I have a split on that string and a foreach loop which creates the task.

In the task itself the function I call needs the full object but with one rssProvider. However when I change the value of that property to the value in the foreach the other tasks will fail as they will get the same single value from the task which runs first.

Any ideas how I should restructure the logic? Thanks!

My code:

        List<Task<ResponseOBJ>> tasks = new List<Task<ResponseOBJ>>();
        // get List of rssProviders
        string[] providers = request.requestBody.rssProvider.Split(',');

        //go through each provider
        foreach (string provider in providers)
        {
            Task<ResponseOBJ> task = Task.Factory.StartNew<ResponseOBJ>(() =>
                {
                    request.requestBody.rssProvider = provider;
                    doStuff(request);
                }
            tasks.Add(task);
        }

        Task.WaitAll(tasks.ToArray());

---

I would create a copy constructor in your Request object which copies the content of the original Request and creates a fresh one:

public class Request
{
    public Request(Request oldRequest)
    {
          // initalize new request from the old
    }
}

And then change my code to create a new request per task:

 List<Task<ResponseOBJ>> tasks = new List<Task<ResponseOBJ>>();
    // get List of rssProviders
 string[] providers = request.requestBody.rssProvider.Split(',');

    //go through each provider
    foreach (string provider in providers)
    {
        Task<ResponseOBJ> task = Task.Factory.StartNew<ResponseOBJ>(() =>
            {
                request.requestBody.rssProvider = provider;
                var newRequest = new Request(request);               
                doStuff(newRequest);
            }
        tasks.Add(task);
    }

    Task.WaitAll(tasks.ToArray());    

---

One option might be to change doStuff(request) to doStuff(request, provider) and remove the line request.requestBody.rssProvider = provider; , and then change your doStuff accordingly.

    foreach (string provider in providers)
    {
        Task<ResponseOBJ> task = Task.Factory.StartNew<ResponseOBJ>(() =>
            {
                doStuff(request, provider);
            }
        tasks.Add(task);
    }

Another option (as also mentioned in the above comments) is to create a new request object for each provider.

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