Question

I would like call HttpWebRequest on another thread as UI, because I must make 200 request or server and downloaded image.

My scenation is that I make a request on server, create image and return image. This I make in another thread. I use Task class, but it call automaticaly Dispose method on all object created in task scope. So I return null object from this method.

    public BitmapImage CreateAvatar(Uri imageUri, int sex)
    {
        if (imageUri == null)
            return CreateDefaultAvatar(sex);

        BitmapImage image = null;

        new Task(() =>
        {
            var request = WebRequest.Create(imageUri);
            var response = request.GetResponse();
            using (var stream = response.GetResponseStream())
            {
                Byte[] buffer = new Byte[response.ContentLength];
                int offset = 0, actuallyRead = 0;
                do
                {
                    actuallyRead = stream.Read(buffer, offset, buffer.Length - offset);
                    offset += actuallyRead;
                } while (actuallyRead > 0);


                    image = new BitmapImage
                    {
                        CreateOptions = BitmapCreateOptions.None,
                        CacheOption = BitmapCacheOption.OnLoad
                    };
                    image.BeginInit();

                    image.StreamSource = new MemoryStream(buffer);

                    image.EndInit();

                    image.Freeze();

            }
        }).Start();

        return image;
    }

How avoid it? Thank

Answer 1

You don’t wait for the Task.

public BitmapImage CreateAvatar(Uri imageUri, int sex)
{
   BitmapImage image = null;

   new Task(() =>
    {
        ....
    }).Start();


   return image;  // But the task is still running ...
} 

To solve it, you would have to Wait() on the Task but then it would be better not to use a task at all here.

A real solution will have to be worked out in the wider program.