I have the following:
wc.DownloadDataCompleted += Wc_DownloadDataCompleted;
FileStream f = File.OpenWrite(insLoc + "\\update.zip");
wc.DownloadDataAsync(new Uri("http://example.com/file.zip"), installLoc + "\\file.zip");
(and in a separate function)
private void Wc_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e)
{
if (e.Error == null) {
MessageBox.Show("Download success");
}
else { MessageBox.Show("Download failed"); }
f.Flush();
f.Dispose();
}
When I check the file it is supposed to be downloading to, it exists, but there is nothing in it (ie, it is 0 bytes). I have flushed the FileStream after the download has finished, so what is happening? I have a progress bar as well, and it slowly increases to 100% so I know it's downloading the ZIP file, and the "Download Success" messagebox is shown.
Thanks in advance!
You should use the callback function to save the resulting file (represented as a byte array passed as second argument):
wc.DownloadDataCompleted += Wc_DownloadDataCompleted;
wc.DownloadDataAsync(new Uri("http://example.com/file.zip"));
and then:
private void Wc_DownloadDataCompleted(object sender, DownloadDataCompletedEventArgs e)
{
if (e.Error == null)
{
string resultFile = Path.Combine(insLoc, "update.zip");
System.IO.File.WriteAllBytes(resultFile, e.Result);
MessageBox.Show("Download success");
}
else
{
MessageBox.Show("Download failed");
}
}
Now you can quickly see that using this method the entire file is loaded in memory as a byte array before flushing it to the file system. This is hugely inefficient especially if you are downloading large files. For this reason it is recommended to use the DownloadFileAsync method instead.
wc.DownloadFileCompleted += Wc_DownloadFileCompleted;
string resultFile = Path.Combine(insLoc, "update.zip");
var uri = new Uri("http://example.com/file.zip");
wc.DownloadFileAsync(uri, resultFile);
and the corresponding callback:
private void Wc_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
{
if (e.Error == null)
{
MessageBox.Show("Download success");
}
else
{
MessageBox.Show("Download failed");
}
}
I would use DownloadFileTaskAsync method of WebClient which I find very simple to use..
await wc.DownloadFileTaskAsync(new Uri("http://example.com/file.zip"), installLoc + "\\file.zip");
That is all. If you want to see the download progress, you can attach to DownloadProgressChanged event.
Related
I am trying to download a large file(around 1GB) my server.When I start downloading I am unable to use the app till the download completes. It is blocking the UI and its becoming unresponsive.
In below code I am calling DownloadFile method when the user download button on the UI.And then download starts, but the UI is freezed.
I read that DownloadFileAsync won't block the UI. But here its blocking. How to use it in correct way. There are several answers but none is working when I am testing.
Code:
Button call:
private void Button_Click(object sender, RoutedEventArgs e)
{
Debug.WriteLine("1");
DownloadGamefile DGF = new DownloadGamefile();
Debug.WriteLine("2" + Environment.CurrentDirectory);
DGF.DownloadFile("URL(https link to zip file)", Environment.CurrentDirectory + #"\ABC.zip");
Debug.WriteLine("3");
}
Download code:
class DownloadGamefile
{
private volatile bool _completed;
public void DownloadFile(string address, string location)
{
WebClient client = new WebClient();
Uri Uri = new Uri(address);
_completed = false;
client.DownloadFileCompleted += new AsyncCompletedEventHandler(Completed);
client.DownloadProgressChanged += new DownloadProgressChangedEventHandler(DownloadProgress);
client.DownloadFileAsync(Uri, location);
}
private void DownloadProgress(object sender, DownloadProgressChangedEventArgs e)
{
// Displays the operation identifier, and the transfer progress.
Console.WriteLine("{0} downloaded {1} of {2} bytes. {3} % complete...",
(string)e.UserState,
e.BytesReceived,
e.TotalBytesToReceive,
e.ProgressPercentage);
}
private void Completed(object sender, AsyncCompletedEventArgs e)
{
if (e.Cancelled == true)
{
Console.WriteLine("Download has been canceled.");
}
else
{
Console.WriteLine("Download completed!");
}
_completed = true;
}
}
Please refer to this link. The actual problem is getting lots of feedback about the number of bytes downloaded(about progress of download process). Take a timer to get progress for every 2 seconds or any time, this solved the problem.
Before you flag this as a duplicate, yes there are questions just like this, i've looked at all of them and still couldn't get this working. I'm trying to code in a feature that downloads and runs a .exe file but it doesn't download, run or do anything. I even removed the try catches to find an error or error codes but I have non, so I have no idea where i'm going wrong, here is my code for it
public test_Configuration()
{
InitializeComponent();
}
Uri uri = new Uri("http://example.com/files/example.exe");
string filename = #"C:\Users\**\AppData\Local\Temp\example.exe";
private void button1_Click(object sender, EventArgs e)
{
try
{
if(File.Exists(filename))
{
File.Delete(filename);
}
else
{
WebClient wc = new WebClient();
wc.DownloadDataAsync(uri, filename);
wc.DownloadProgressChanged += new DownloadProgressChangedEventHandler(wc_DownloadProgressChanged);
wc.DownloadFileCompleted += new AsyncCompletedEventHandler(wc_DownloadFileCompleted);
}
}
catch(Exception ex)
{
MessageBox.Show(ex.Message.ToString());
}
}
private void wc_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
if (progressBar1.Value == progressBar1.Maximum)
{
progressBar1.Value = 0;
}
}
private void wc_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
{
if(e.Error == null)
{
MessageBox.Show("Download complete!, running exe", "Completed!");
Process.Start(filename);
}
else
{
MessageBox.Show("Unable to download exe, please check your connection", "Download failed!");
}
Change DownloadDataAsync to DownloadFileAsync.
wc.DownloadFileAsync(uri, filename);
This code helped me out quite a bit with updating a file, so I thought I would show my twist in the hopes that someone else out there has a similar requirement as me.
I needed this code to do the following when a button was clicked:
Grab a file from a sever and store it locally in AppData\Temp.
Keep my user up-to-date of install progress (an installer is downloaded).
If successfully downloaded (note the removal of the else after deleting old file check), launch "daInstaller.exe", whilst terminating the current running program.
And if said file already exist (i.e. the old "daIstaller.exe"), delete prior to copying new file to AppData\Temp.
Don't forget to keep the file names the same, else you'll be leaving more trash in that AppData\Temp folder.
private void button1_Click(object sender, EventArgs e)
{
Uri uri = new Uri("http://example.com/files/example.exe");
filename = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), "Temp/example.exe");
try
{
if (File.Exists(filename))
{
File.Delete(filename);
}
WebClient wc = new WebClient();
wc.DownloadFileAsync(uri, filename);
wc.DownloadProgressChanged += new DownloadProgressChangedEventHandler(wc_DownloadProgressChanged);
wc.DownloadFileCompleted += new AsyncCompletedEventHandler(wc_DownloadFileCompleted);
}
catch (Exception ex)
{
MessageBox.Show(ex.Message.ToString());
}
}
private void wc_DownloadProgressChanged(object sender, DownloadProgressChangedEventArgs e)
{
progressBar1.Value = e.ProgressPercentage;
if (progressBar1.Value == progressBar1.Maximum)
{
progressBar1.Value = 0;
}
}
private void wc_DownloadFileCompleted(object sender, AsyncCompletedEventArgs e)
{
if (e.Error == null)
{
Process.Start(filename);
Close();
Application.Exit();
}
else
{
MessageBox.Show("Unable to download exe, please check your connection", "Download failed!");
}
}
I have a WinForms application which uses a backgroundworker for downloading images from given urls. For the download I use a backgroundworker.
The application is running fine when started, and the download happens as planned, but when the worker is done and I click the downloadbutton again to start downloading from another url, the backgroundworker doesn't do anything.
I fixed that problem temporarily by calling application.restart() when the worker is done, which works but can't be here longer than it has to.
Worker-Code:
// initialization of worker is done in constructor of my class
downloadWorker.WorkerReportsProgress = true;
downloadWorker.WorkerSupportsCancellation = true;
downloadWorker.DoWork += new DoWorkEventHandler(worker_doWork);
downloadWorker.ProgressChanged += new ProgressChangedEventHandler(worker_progressChanged);
downloadWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(worker_runWorkerCompleted);
// ...
private void worker_doWork(object sender, DoWorkEventArgs e)
{
WebClient downloadClient = new WebClient();
HttpWebRequest HttpReq = (HttpWebRequest)WebRequest.Create(url);
HttpWebResponse response;
try
{
response = (HttpWebResponse)HttpReq.GetResponse();
}
catch (WebException ex)
{
response = (HttpWebResponse)ex.Response;
}
if (response.StatusCode == HttpStatusCode.NotFound)
MessageBox.Show("Website not found");
if (response.StatusCode == HttpStatusCode.OK)
{
for(int i=0; i<3;i++)
{
string image = getImageUrl(url,i);
downloadWorker.ReportProgress(i);
image = WebUtility.HtmlDecode(image);
string saveName = "img_"+i+".png";
try
{
downloadClient.DownloadFile(image, saveName);
}
catch (Exception ex)
{
MessageBox.Show(ex.StackTrace);
}
}
}
}
private void worker_progressChanged(object sender, ProgressChangedEventArgs e)
{
rtxtStatus.AppendText("Downloade Image" + e.ProgressPercentage + " of 3");
}
private void worker_runWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
MessageBox.Show("Download completed");
}
edit:
if (e.Error != null)
{
MessageBox.Show(e.Error.ToString());
}
To avoid any misunderstandings: The backgroundWorker is definetely running at the second time, and it is not an error of the reportProgress-method, since I get the same thing when I dont report anything.
edit no. 2:
I found out where the error came from: at the second run, the for-loop is completely skipped. But that doesn't make any sense for me either... There can't be any other value still be in because I have a completely new instance of the class, can it? But anyway, if it just skipped the method the worker still should exit which it doesn't do. For testing, I added a MessageBox after the for-loop, which is not executed after the second run.
private void button2_Click(object sender, EventArgs e)
{
SaveFileDialog Sdialog = new SaveFileDialog();
Sdialog.ShowDialog();
Sdialog.FileOk += Sdialog_FileOk;
}
void Sdialog_FileOk(object sender, CancelEventArgs e)
{
try
{
StreamWriter FileProtocol = new StreamWriter(((SaveFileDialog)sender).FileName);
FileProtocol.Write(textBox3.Text);
FileProtocol.Close();
MessageBox.Show("File is write ok");
}
catch (Exception)
{
MessageBox.Show("Unknown Error. File is not write");
}
}
Why does event FileOk not work?
Because you need to hook the event up before calling ShowDialog(). When you call ShowDialog() it stops processing on that thread and waits for a response.
So, instead of this:
Sdialog.ShowDialog();
Sdialog.FileOk += Sdialog_FileOk;
do this:
Sdialog.FileOk += Sdialog_FileOk;
Sdialog.ShowDialog();
To use the DialogResult to simplify you're workflow, just do this:
if (Sdialog.ShowDialog() == DialogResult.OK)
{
try
{
StreamWriter FileProtocol =
new StreamWriter(Sdialog.FileName);
FileProtocol.Write(textBox3.Text);
FileProtocol.Close();
MessageBox.Show("File is write ok");
}
catch (Exception)
{
MessageBox.Show("Unknown Error. File is not write");
}
}
ALSO: instead of doing this:
StreamWriter FileProtocol =
new StreamWriter(Sdialog.FileName);
FileProtocol.Write(textBox3.Text);
FileProtocol.Close();
how about simplify it to this:
File.AppendAllText(Sdialog.FileName, textBox3.Text);
The benefit is two fold:
The code is clearly much more concise, and;
The code is safer because it manages the un-managed resources appropriately for you.
I am using Live api to download SkyDrive files.
My code has a download click event which triggers the OnDownloadedCompleted function.
OnDownloadedCompleted function copies the file to "filename".
and calls the DefaultLaunch(), which takes in the "filename" and tries to launch it by the default program in windows phone 8.
When i execute this code (The file downloaded is a OneNote file) OneNote opens and says that the file can't be open.
Can anyone please help me validate this code?
Thanks a lot!
private void btnDownload_Click(object sender, RoutedEventArgs e)
{
if (App.Current.LiveSession == null)
{
infoTextBlock.Text = "You must sign in first.";
}
else
{
LiveConnectClient client = new LiveConnectClient(App.Current.LiveSession);
client.DownloadCompleted += new EventHandler<LiveDownloadCompletedEventArgs>(OnDownloadCompleted);
client.DownloadAsync("file_id");
}
}
The code for OnDownloadCompleted is
void OnDownloadCompleted(object sender, LiveDownloadCompletedEventArgs e)
{
if (e.Result != null)
{
var filestream = File.Create(#"filename");
e.Result.Seek(0, SeekOrigin.Begin);
e.Result.CopyTo(filestream);
filestream.Close();
DefaultLaunch();
e.Result.Close();
}
else
{
infoTextBlock.Text = "Error downloading image: " + e.Error.ToString();
}
}
The code for Default launch function is
async void DefaultLaunch()
{
try
{
string imageFile = #"File.one";
var file = await Windows.ApplicationModel.Package.Current.InstalledLocation.GetFileAsync(imageFile);
var success = await Windows.System.Launcher.LaunchFileAsync(file);
if (success)
{}
else
{}
}
catch (Exception e)
{
Console.WriteLine(e.StackTrace);
Console.WriteLine(e.ToString());
}
}
try this tutorial.. http://msdn.microsoft.com/en-us/live/ff519582.aspx.. it is given there how to use live sdk in windows 8 platform