How to download multiple files using webclient ?

Question

one single file is fine but when i loop over the List of links it's saving to the hard disk many empty files.

private void btnGetDownload_Click(object sender, EventArgs e)  
        {  
            for (int i = 0; i < videosLinks.Count; i++)  
            {  
                string fileName = System.IO.Path.GetFileName(videosLinks[i]);  
                DownloadFile(videosLinks[i], @"D:\Videos\videos\" + fileName);  
            }  
        }  
  
        public void DownloadFile(string urlAddress, string location)  
        {  
            Stopwatch sw = new Stopwatch();  
            using (WebClient webClient = new WebClient())  
            {  
                webClient.Headers.Add("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:67.0) Gecko/20100101 Firefox/67.0 Chrome");  
                webClient.DownloadFileCompleted += new AsyncCompletedEventHandler((sender, e) => Completed(sender, e, sw));  
                webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler((sender, e) => ProgressChanged(sender, e, sw));  
                Uri URL = new Uri(urlAddress);  
                sw.Start();  
                try  
                {  
                    webClient.DownloadFileAsync(URL, location);  
                }  
                catch (Exception ex)  
                {  
                    MessageBox.Show(ex.Message);  
                }  
            }  
        }  
  
        private void ProgressChanged(object sender, DownloadProgressChangedEventArgs e, Stopwatch sw)  
        {  
            progressBar1.Value = e.ProgressPercentage;  
            lblFileName.Text = string.Format("data", string.Format("{0} / {1} MB",  
               (e.BytesReceived / 1024d / 1024d).ToString("0.00"),  
               (e.TotalBytesToReceive / 1024d / 1024d).ToString("0.00")));  
            btnGetDownload.Text =  "Downloading...";  
            label1.Text =  string.Format("{0} Kb/s", (e.BytesReceived / 1024d / sw.Elapsed.TotalSeconds).ToString("0.00"));  
        }  
  
        private void Completed(object sender, AsyncCompletedEventArgs e, Stopwatch sw)  
        {  
            if (e.Cancelled == true)  
            {  
                btnGetDownload.Text =  "Fails.";  
                sw.Stop();  
            }  
            else  
            {  
                btnGetDownload.Text =  "Finish.";  
                label1.Text = "0 Kb/s";  
                sw.Stop();  
            }  
        }  

If i'm doing in the button click event without a loop just :

 string fileName = System.IO.Path.GetFileName(videosLinks[0]);  
 DownloadFile(videosLinks[0], @"D:\Videos\videos\" + fileName);  

this will work fine but i want to download each file one by one from the List videosLinks.

i tried to search and use httpclient and async await but could not fine a complete project and what i tried so far didn't work at all. not sure how to use the results i found mostly in stackoverflow site that's why i'm using webclient. the problem is how to download all the files in the list one by one ?

Answer 1

This is working fine :

private void btnGetDownload_Click(object sender, EventArgs e)  
        {  
            string fileName = System.IO.Path.GetFileName(videosLinks[0]);  
            DownloadFile(videosLinks[0], @"D:\Videos\videos\" + fileName);  
        }  
  
        public void DownloadFile(string urlAddress, string location)  
        {  
            Stopwatch sw = new Stopwatch();  
            using (WebClient webClient = new WebClient())  
            {  
                webClient.Headers.Add("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:67.0) Gecko/20100101 Firefox/67.0 Chrome");  
                webClient.DownloadFileCompleted += new AsyncCompletedEventHandler((sender, e) => Completed(sender, e, sw));  
                webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler((sender, e) => ProgressChanged(sender, e, sw));  
                Uri URL = new Uri(urlAddress);  
                sw.Start();  
                try  
                {  
                    webClient.DownloadFileAsync(URL, location);  
                }  
                catch (Exception ex)  
                {  
                    MessageBox.Show(ex.Message);  
                }  
            }  
        }  
  
        private void ProgressChanged(object sender, DownloadProgressChangedEventArgs e, Stopwatch sw)  
        {  
            progressBar1.Value = e.ProgressPercentage;  
            lblFileName.Text = string.Format("data", string.Format("{0} / {1} MB",  
               (e.BytesReceived / 1024d / 1024d).ToString("0.00"),  
               (e.TotalBytesToReceive / 1024d / 1024d).ToString("0.00")));  
            btnGetDownload.Text =  "Downloading...";  
            label1.Text =  string.Format("{0} Kb/s", (e.BytesReceived / 1024d / sw.Elapsed.TotalSeconds).ToString("0.00"));  
        }  
  
        private void Completed(object sender, AsyncCompletedEventArgs e, Stopwatch sw)  
        {  
            if (e.Cancelled == true)  
            {  
                btnGetDownload.Text =  "Fails.";  
                sw.Stop();  
            }  
            else  
            {  
                btnGetDownload.Text =  "Finish.";  
                label1.Text = "0 Kb/s";  
                sw.Stop();  
  
                if (videosLinks.Count > 0)  
                {  
                    videosLinks.RemoveAt(0);  
                    string fileName = System.IO.Path.GetFileName(videosLinks[0]);  
                    DownloadFile(videosLinks[0], @"D:\Videos\videos\" + fileName);  
                }  
            }  
        }