将HttpContext传递给Task.Run线程

Question

I'm trying to pass HttpContext.Current to the thread created via Task.Run . As I have a Transaction ID in in HttpContext.Items , which I'll need in the thread.

public static Task<TResult> RunWithContext<TResult>(Func<TResult> function)
{
    var context = HttpContext.Current;                        
    return Task.Run(()=> { RequestHelper.SaveHttpContextInThread(context); return function(); } );
}

public static void SaveHttpContextInThread(HttpContext context)
{
    Thread.SetData(Thread.GetNamedDataSlot(RequestHelper.THREAD_SLOT_NAME), context);
}


var response = TaskHelper.RunWithContext(() => _service.UpdateJob(jobjsonstring));
var jobData = JObject.Parse(response.Result); //Compiler error here

But a compiler error

'Argument 1: cannot convert from 'System.Threading.Tasks.Task' to 'string'

occurs in the last line.

Seems to be an issue with the way I'm returning from the anonymous method.

---

Update

It seems _service.UpdateJob was returning Task but I was expecting it to return Job object, Apologies.

Actual Problem: In a WebAPI we want to run some task in a new thread. There is a value TransactionID in HttpContext.Items. We want the newly created thread to be able to read TransactionID. The above approach was to pass the entire HttpContext to the new thread.

Answer 1

It can get quite confusing with the nested use of tasks, especially without the use async / await .

The _ service.UpdateJob(jobjsonstring) returns a Task . Therefore Task.Run which executes this function returns a Task object with a Task as result.

In order to get the Result of the _ service.UpdateJob call you have to use response.Result.Result .

 var jobData = JObject.Parse(response.Result.Result);

Another alternative (without async/await) is to return the Result inside the function, eg

var response = TaskHelper.RunWithContext(() => _service.UpdateJob(jobjsonstring).Result);