Problem in working with async and await ?

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Hi
I am trying to upload files to Azure Blob Storage and after successful upload adding the filename to a list for my further operation. When i am doing synchronous it works fine but when i am doing async the error occured.
Error : Collection was modified; enumeration operation may not execute.

C#

foreach(var file in files)
{
   // .....
   await blockBlob.UploadFromStreamAsync(fs);
   listOfMovedLabelFiles.Add(fileName);
}

C#

if (listOfMovedLabelFiles.Count > 0) // error point
{
    // my code for further operation
}

Is there any way to wait till all the async operations get completed.

Posted 5-Jun-14 0:58am

Vi(ky

Updated 5-Jun-14 4:52am

v6

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Comments

Sampath Lokuge 5-Jun-14 7:03am

Is this Asp.net forms or MVC ?

Vi(ky 5-Jun-14 7:04am

It is console application.

Herman<T>.Instance 5-Jun-14 8:06am

because of asynchronity your lists expands in the background. Better do the job in the background and raise an event when a filename must be added to the list

Rahul Kumar 5-Jun-14 10:28am

and how to implement it, any sample or link.

Herman<T>.Instance 5-Jun-14 18:15pm

what is the problem for you, the async or the event?

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This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Sampath Lokuge · Answer 1 · 2014-06-05T03:08:00

If it's a console app then you have to use Async is as below.

Note: This is just a sample.Adjust it according to your app.

class Program
{
  static int Main(string[] args)
  {
    try
    {
      return AsyncContext.Run(() => MainAsync(args));
    }
    catch (Exception ex)
    {
      Console.Error.WriteLine(ex);
      return -1;
    }
  }

  static async Task<int> MainAsync(string[] args)
  {
    ...
  }
}

Read for more info : Async Console Programs

Problem in working with async and await ?

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Problem in working with async and await ?

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