Download file and automatically save it to folder

Question

I m trying to make a UI for downloading files from my site  The site have zip-files and these need to be downloaded to the directory entered by the user  However  I can t succeed to download the file  it just opens up from a temporary folder   Code   private void webBrowser1 Navigating object sender  WebBrowserNavigatingEventArgs e            e Cancel   true          string filepath   null              filepath   textBox1 Text              WebClient client   new WebClient                client DownloadFileCompleted    new AsyncCompletedEventHandler client DownloadFileCompleted               client DownloadFileAsync e Url  filepath       Full sourcecode  http   en paidpaste com LqEmiQ

User · Answer

If you don t want to use  WebClient  or and need to use the System Windows Forms WebBrowser e g  because you want simulate a login first  you can use this extended WebBrowser which hooks the  URLDownloadToFile  Method from the Windows URLMON Lib and uses the Context of the WebBrowser  Infos  http   www pinvoke net default aspx urlmon URLDownloadToFile 20 html  using System  using System IO  using System Runtime InteropServices  using System Windows Forms   namespace dataCoreLib Net Webpage           public class WebBrowserWithDownloadAbility   WebBrowser                            lt summary gt                  The URLMON library contains this function  URLDownloadToFile  which is a way                 to download files without user prompts   The ExecWB   SAVEAS   function always                 prompts the user  even if  DONTPROMPTUSER parameter is specified  for  internet                 security reasons    This function gets around those reasons                   lt  summary gt                   lt param name  callerPointer  gt Pointer to caller object  AX   lt  param gt                   lt param name  url  gt String of the URL  lt  param gt                   lt param name  filePathWithName  gt String of the destination filename path  lt  param gt                   lt param name  reserved  gt  reserved   lt  param gt                   lt param name  callBack  gt A callback function to monitor progress or abort  lt  param gt                   lt returns gt 0 for okay  lt  returns gt                  source  http   www pinvoke net default aspx urlmon URLDownloadToFile 20 html              DllImport  urlmon dll   CharSet   CharSet Auto  SetLastError   true               static extern Int32 URLDownloadToFile                   MarshalAs UnmanagedType IUnknown   object callerPointer                   MarshalAs UnmanagedType LPWStr   string url                   MarshalAs UnmanagedType LPWStr   string filePathWithName                  Int32 reserved                  IntPtr callBack                      lt summary gt                  Download a file from the webpage and save it to the destination without promting the user                  lt  summary gt                   lt param name  url  gt the url with the file lt  param gt                   lt param name  destinationFullPathWithName  gt the absolut full path with the filename as destination lt  param gt                   lt returns gt  lt  returns gt              public FileInfo DownloadFile string url  string destinationFullPathWithName                                URLDownloadToFile null  url  destinationFullPathWithName  0  IntPtr Zero                   return new FileInfo destinationFullPathWithName

User · Answer

Well  your solution almost works  There are a few things to take into account to keep it simple    Cancel the default navigation only for specific URLs you know a download will occur  or the user won t be able to navigate anywhere  This means you musn t change your website download URLs  DownloadFileAsync doesn t know the name reported by the server in the Content-Disposition header so you have to specify one  or compute one from the original URL if that s possible  You cannot just specify the folder and expect the file name to be retrieved automatically  You have to handle download server errors from the DownloadCompleted callback because the web browser control won t do it for you anymore    Sample piece of code  that will download into the directory specified in textBox1  but with a random file name  and without any additional error handling   private void webBrowser1 Navigating object sender  WebBrowserNavigatingEventArgs e           change this to match your URL  For example  if the URL always is something like  getfile php file xxx   try e Url ToString   Contains  getfile php           if  e Url ToString   EndsWith   zip              e Cancel   true          string filePath   Path Combine textBox1 Text  Path GetRandomFileName             var client   new WebClient            client DownloadFileCompleted    client DownloadFileCompleted          client DownloadFileAsync e Url  filePath            private void client DownloadFileCompleted object sender  AsyncCompletedEventArgs e        MessageBox Show  File downloaded        This solution should work but can be broken very easily  Try to consider some web service listing the available files for download and make a custom UI for it  It ll be simpler and you will control the whole process

User · Answer

Why not just bypass the WebClient s file handling pieces altogether  Perhaps something similar to this       private void webBrowser1 Navigating object sender  WebBrowserNavigatingEventArgs e                e Cancel   true          WebClient client   new WebClient             client DownloadDataCompleted    new DownloadDataCompletedEventHandler client DownloadDataCompleted            client DownloadDataAsync e Url              void client DownloadDataCompleted object sender  DownloadDataCompletedEventArgs e                string filepath   textBox1 Text          File WriteAllBytes filepath  e Result           MessageBox Show  File downloaded

User · Answer

Take a look at http   www csharp-examples net download-files  and msdn docs on webclient  http   msdn microsoft com en-us library system net webclient aspx  My suggestion is try the synchronous download as its more straightforward   you might get ideas on whether webclient parameters are wrong or the file is in incorrect format while trying this   Here is a code sample    private void btnDownload Click object sender  EventArgs e      string filepath   textBox1 Text    WebClient webClient   new WebClient      webClient DownloadFileCompleted    new AsyncCompletedEventHandler Completed     webClient DownloadProgressChanged    new DownloadProgressChangedEventHandler ProgressChanged     webClient DownloadFileAsync new Uri  http   mysite com myfile txt    filepath      private void ProgressChanged object sender  DownloadProgressChangedEventArgs e      progressBar Value   e ProgressPercentage     private void Completed object sender  AsyncCompletedEventArgs e      MessageBox Show  Download completed

User · Answer

A much simpler solution would be to download the file using Chrome  In this manner you don t have to manually click on the save button    using System  using System Diagnostics  using System ComponentModel   namespace MyProcessSample       class MyProcess               public static void Main                         Process myProcess   new Process                myProcess Start  chrome exe   http   www com newfile zip

User · Answer

My program does exactly what you are after  no prompts or anything  please see the following code   This code will create all of the necessary directories if they don t already exist   Directory CreateDirectory C  dir dira dirb       This code will create all of these directories     This code will download the given file to the given directory  after it has been created by the previous snippet   private void install                 WebClient webClient   new WebClient                                                                Creates a webclient         webClient DownloadFileCompleted    new AsyncCompletedEventHandler Completed                        Uses the Event Handler to check whether the download is complete         webClient DownloadProgressChanged    new DownloadProgressChangedEventHandler ProgressChanged       Uses the Event Handler to check for progress made         webClient DownloadFileAsync new Uri  http   www com newfile zip      C newfile zip                 Defines the URL and destination directory for the downloaded file         So using these two pieces of code you can create all of the directories and then tell the downloader  that doesn t prompt you to download the file to that location

[c#] Download file and automatically save it to folder

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