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C # get object from asyncron task

I am just getting started with thread programming in C #. And I really don't know if this community is right to ask such questions. If not, they're sorry.

I have two functions: start () and status (). In start () I create a new task, for example:

start() {
   for each(dir => ListOfAllDirs) {
       new Task(() => { yr.LoadAllFiles(dir); }).Start();
   }
 }

so I have about 200 parallel tasks running with this code:

class yr
{
    List<Values> rv = new List<Values>();
    public List<Values> LoadAllFiles(string dir)
    {
       [...DoStuff...]
       rv.Add(...);
       rv.Add(...);
       rv.Add(...);
    }

}

So I don't know how to access> 200 running threads to get the data before it runs out. I'm looking for sth. as:

status(dir) {
    int count = GetTaskByName[dir].rv.Count; (????)
    Console.WriteLine("Dir " + dir + "->" + count + "files checked");
}

And the final conclusion:

Dir AA -> 19 files checkes
Dir AB -> 12 files checkes
Dir BB -> 49 files checkes
Dir AA -> 29 files checkes

So to be clear: 200 dirs, 200 tasks, everything works asyncron. How to access a specific Task / Get data from a running task.

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2 answers


Apparently you need to take 200 directories and calculate the result for each one. PLINQ makes this extremely simple:

var results =
ListOfAllDirs
.AsParallel()
.Select(dir => new { dir, result = yr.LoadAllFiles(dir) })
.ToList();

And here is a list of directories and the result of calculations.



You can do it manually and with tasks. In this case, you probably need a sequence like this:

  • Create all tasks and save them
  • Use Task.WaitAll to wait for completion
  • Use Task.Result for each task to get the result
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Are you looking for something like this?

var task = Task<List<values>>.Run((() => { return yr.LoadAllFiles(dir);}));
List<values> result = task.Result;


If it has a result type, you can access the result of the task. This waits for the task to complete and the result is received.

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