Download file through http in C# Windows App

Check this out, it should get you started with a solution:

HttpWebRequest request = (HttpWebRequest)WebRequest.Create("http://dropshipdirect.com/warehouse/vendor_export_speedup.php?use_link=on&ve_sid=fal9vgtv5hg3yo4ofhiqhiuogmy3dbji");
WebResponse response = request.GetResponse();
string containsfilename = response.Headers[1];

The obvious solution is to put up a SaveFileDialog. If you want no user interaction, you will have to make up a file name, for example by appending a UID to the path part of the URL, or doing something with the query parameters.

Reading the comments, it seems that you have another issue, which is that the page you're actually looking at is not the file you want to download. You may have to grab that page, look through it for the 'real' link, and make another HTTP request to get the file (and don't forget the Referer header on that one).

I have developed a fully-fledged HTTPDowloader with important feature — continue interrupted downloads.
It is a console application (in my opinion, the best approach for such task as it can be easily used in batch), but adaptation for UI will be very easy (always use a separate thread(s) for downloads).

Here is the complete source code:
how to download a file from internet[^].

(Note: a biggest part of this code is dedicated to naming of the output file. Input parameters are URL and output file; if output file name is not specified, it is constructed based on URL in unique and uniform manner; the naming is important for continuation of downloads interrupted during previous run-time.)

—SA

private void DownloadFile()
       {
           
           wc.DownloadProgressChanged += WcOnDownloadProgressChanged;
           wc.DownloadFileCompleted += WcOnDownloadFileCompleted;
           string downloadUrl = ConfigurationSettings.AppSettings["fileDownloadPath"] ;


           wc.DownloadFileAsync(new Uri(downloadUrl), @"C:\\fileName" );
           handle.WaitOne(); // wait for the async event to complete

       }

       private void WcOnDownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
       {
           if (!e.Cancelled && e.Error == null)
           {
               //async download completed successfully

           }
           handle.Set(); // in both the case let the void main() know that async event had finished so that i can quit
       }

       private void WcOnDownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
       {
           // handle the progres in case of async
           //e.ProgressPercentage

       }
       private void butsync_Click(object sender, EventArgs e)
       {
           DownloadFile();
}

may this help you