web client DownloadFileCompleted get file name

Question

I tried to download file like this:

WebClient _downloadClient = new WebClient();

_downloadClient.DownloadFileCompleted += DownloadFileCompleted;
_downloadCl         


        

Answer 1

One way is to create a closure.

        WebClient _downloadClient = new WebClient();        
        _downloadClient.DownloadFileCompleted += DownloadFileCompleted(_filename);
        _downloadClient.DownloadFileAsync(current.url, _filename);

Which means your DownloadFileCompleted needs to return the event handler.

        public AsyncCompletedEventHandler DownloadFileCompleted(string filename)
        { 
            Action action = (sender,e) =>
            {
                var _filename = filename;

                if (e.Error != null)
                {
                    throw e.Error;
                }
                if (!_downloadFileVersion.Any())
                {
                    complited = true;
                }
                DownloadFile();
            };
            return new AsyncCompletedEventHandler(action);
        }

The reason I create the variable called _filename is so that the filename variable passed into the DownloadFileComplete method is captured and stored in the closure. If you didn't do this you wouldn't have access to the filename variable within the closure.