如何确保我下载的文件已完成？

Question

I have this application which allows me to download certain files from the internet when I press a button. However.. I have no idea how to make sure that the file has actually finished downloading.

I'm currently using the good old WebClient method of downloading files

    using (WebClient client = new WebClient())
    {
        client.DownloadFileAsync(new System.Uri(requestUrl), combinedPaths);
    }

There is no need to show more of the code really since the download function is very simple and straight forward. I need to figure out how to keep track of the file that you are downloading to see how much it has downloaded for example 1 / 100%.. I have a very good ISP with 250 Mb/s download speed so its really hard for me to see if it has actually been finished or not.

Answer 1

You can fire WebClient.DownloadFileCompleted event and do something with it:

client.DownloadFileCompleted += new AsyncCompletedEventHandler(DownloadFileCallback);

To know the status of the download you can subscribe to another event handler:

client.DownloadProgressChanged += new DownloadProgressChangedEventHandler(DownloadProgressCallback);

Answer 2

The WebClient has an event handler called DownlaodFileCompleted that you can use to trigger when the file has finished downloading :

myWebClient.DownloadFileCompleted += DownloadCompleted;

public static void DownloadCompleted(object sender, AsyncCompletedEventArgs e)
{
    Console.WriteLine("Success");
}