WebClient shutdown after loading

Question

I ran into another problem, my application downloads a file from the Internet, extracts it, deletes it, etc., it works great for the first run, and then when it comes to downloading the next file, it just freezes the download and hangs there forever. There may be something trying to open an already open connection, but I have no idea how to close it, this is my first network work with C #, and I teach myself.

My code is:

  public void start() {
        if (File.Exists("Data/version.txt")) { File.Delete("Data/version.txt"); }
        label1.Text = "Getting update information...";
        WebClient webClient = new WebClient();
        webClient.DownloadFileAsync(new Uri("http://127.0.0.1/update/version.txt"), @"Data/version.txt");
        webClient.DownloadFileCompleted += new AsyncCompletedEventHandler(versionCompleted);
    }

    private void versioncheck() {
        if (File.Exists("Main.exe"))
        {       
            label1.Text = "Contacting update server...";
                var versionInfo = FileVersionInfo.GetVersionInfo("Main.exe");
                string version = versionInfo.ProductVersion;
                string[] nversion = version.Split('.');
                string updateversion = nversion[3];

                int version = Int32.Parse(updateversion);
                ///////////////////////////////////////////////////////////
                StreamReader sr = new StreamReader("Data/version.txt");
                ///////////////////////////////////////////////////////////
                string readline = sr.ReadLine();
                sr.Dispose();
                int serverversion = Int32.Parse(readline);

                if (serverversion > version) {
                    string filenumber = (version+1).ToString();
                    downloadfile(filenumber); 
                }
                else if(serverversion == version){
                    label1.Text = "Game is up to date!";
                    startButton.Enabled = true;
                }

        }
        else { MessageBox.Show("Unexpected Error!", "Error!"); }
    }

    private void ProgressChanged(object sender, DownloadProgressChangedEventArgs e)
    {
        progressBar1.Value = e.ProgressPercentage;
    }

    private void Completed(object sender, AsyncCompletedEventArgs e)
    {
        label1.Text = "Extracting Files...";
        var versionInfo = FileVersionInfo.GetVersionInfo("Main.exe");
        string version = versionInfo.ProductVersion;
        string[] nversion = version.Split('.');
        string updateversion = nversion[3];
        int version = Int32.Parse(updateversion); string nversion = (version + 1).ToString();

        Process proc = Process.Start("update"+nversion+".exe"); // extract in the silent mode
        proc.WaitForExit();
        File.Delete("update" + nversion + ".exe");
        label1.Text = "Checking for more updates...";
        versioncheck();
    }

    private void versionCompleted(object sender, AsyncCompletedEventArgs e) {
        versioncheck();
    }

    private void downloadfile(string filenumber)
    {
        try
        {
            //MessageBox.Show("Download working");
            System.Net.WebClient webClient = new System.Net.WebClient();
            webClient.OpenRead("http://127.0.0.1/Update/update" + filenumber + ".exe");
            Int64 bytes_total = Convert.ToInt64(webClient.ResponseHeaders["Content-Length"]);
            string updatelength = Convert.ToString((bytes_total / 1024).ToString());
            label2.Text = "File size:" + updatelength + "KB";
            ////////////////////////////////////////////////////
            label1.Text = "Downloading Update...";
            webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler(ProgressChanged);
            webClient.DownloadFileAsync(new Uri("http://127.0.0.1/Update/update" + filenumber + ".exe"), @"update"+filenumber+".exe");
            webClient.DownloadFileCompleted += new AsyncCompletedEventHandler(Completed);
            webClient.Dispose();

        }
        catch (WebException )
        {
            MessageBox.Show("Connection error!", "Error!");
            Application.Exit();
        }
        catch (IOException)
        {
            MessageBox.Show("Unknown Error!", "Error!");
            Application.Exit() ;
        }       
    }

Answer 1

If you are using an async operation, you need to use async and wait for the keywords.

U need to remove or close the web client when it is loaded or working.

b1tsh1ft, using.

string version = versionInfo.ProductVersion;
string[] nversion = version.Split('.');

int version = Int32.Parse(updateversion); 
string nversion = (version + 1).ToString();

VS ?

Answer 2

WebClient , IDisposable

using(var webClient = new WebClient())
{
    // do work here
    webClient.DownloadFile(..)
}

. , , . .

StreamReader ( -, IDisposable) using(). , dispose, .