private void WebClientOnDownloadFileCompleted(object sender, AsyncCompletedEventArgs asyncCompletedEventArgs)
        {
            if (asyncCompletedEventArgs.Cancelled)
            {
                return;
            }

            try
            {
                if (asyncCompletedEventArgs.Error != null)
                {
                    throw asyncCompletedEventArgs.Error;
                }

                if (_args.CheckSum != null)
                {
                    CompareChecksum(_tempFile, _args.CheckSum);
                }

                ContentDisposition contentDisposition = null;
                if (_webClient.ResponseHeaders["Content-Disposition"] != null)
                {
                    contentDisposition = new ContentDisposition(_webClient.ResponseHeaders["Content-Disposition"]);
                }

                var fileName = string.IsNullOrEmpty(contentDisposition?.FileName)
                    ? Path.GetFileName(_webClient.ResponseUri.LocalPath)
                    : contentDisposition.FileName;

                var tempPath =
                    Path.Combine(
                        string.IsNullOrEmpty(AutoUpdater.DownloadPath) ? Path.GetTempPath() : AutoUpdater.DownloadPath,
                        fileName);

                if (File.Exists(tempPath))
                {
                    File.Delete(tempPath);
                }

                File.Move(_tempFile, tempPath);

                string installerArgs = null;
                if (!string.IsNullOrEmpty(_args.InstallerArgs))
                {
                    installerArgs = _args.InstallerArgs.Replace("%path%",
                                                                Path.GetDirectoryName(Process.GetCurrentProcess().MainModule.FileName));
                }

                var processStartInfo = new ProcessStartInfo
                {
                    FileName        = tempPath,
                    UseShellExecute = true,
                    Arguments       = installerArgs
                };

                var extension = Path.GetExtension(tempPath);

                if (extension.Equals(".zip", StringComparison.OrdinalIgnoreCase))
                {
                    string installerPath = Path.Combine(Path.GetDirectoryName(tempPath), "ZipExtractor.exe");

                    File.WriteAllBytes(installerPath, Resources.ZipExtractor);

                    string executablePath = Process.GetCurrentProcess().MainModule.FileName;
                    string extractionPath = Path.GetDirectoryName(executablePath);

                    if (!string.IsNullOrEmpty(AutoUpdater.InstallationPath) &&
                        Directory.Exists(AutoUpdater.InstallationPath))
                    {
                        extractionPath = AutoUpdater.InstallationPath;
                    }

                    StringBuilder arguments =
                        new StringBuilder($"\"{tempPath}\" \"{extractionPath}\" \"{executablePath}\"");
                    string[] args = Environment.GetCommandLineArgs();
                    for (int i = 1; i < args.Length; i++)
                    {
                        if (i.Equals(1))
                        {
                            arguments.Append(" \"");
                        }

                        arguments.Append(args[i]);
                        arguments.Append(i.Equals(args.Length - 1) ? "\"" : " ");
                    }

                    processStartInfo = new ProcessStartInfo
                    {
                        FileName        = installerPath,
                        UseShellExecute = true,
                        Arguments       = arguments.ToString()
                    };
                }
                else if (extension.Equals(".msi", StringComparison.OrdinalIgnoreCase))
                {
                    processStartInfo = new ProcessStartInfo
                    {
                        FileName  = "msiexec",
                        Arguments = $"/i \"{tempPath}\""
                    };
                    if (!string.IsNullOrEmpty(installerArgs))
                    {
                        processStartInfo.Arguments += " " + installerArgs;
                    }
                }

                if (AutoUpdater.RunUpdateAsAdmin)
                {
                    processStartInfo.Verb = "runas";
                }

                try
                {
                    Process.Start(processStartInfo);
                }
                catch (Win32Exception exception)
                {
                    if (exception.NativeErrorCode == 1223)
                    {
                        _webClient = null;
                    }
                    else
                    {
                        throw;
                    }
                }
            }
            catch (Exception e)
            {
                MessageBox.Show(e.Message, e.GetType().ToString(), MessageBoxButtons.OK, MessageBoxIcon.Error);
                _webClient = null;
            }
            finally
            {
                Close();
            }
        }
        private static object CheckUpdate(Assembly mainAssembly)
        {
            var companyAttribute =
                (AssemblyCompanyAttribute)GetAttribute(mainAssembly, typeof(AssemblyCompanyAttribute));
            string appCompany = companyAttribute != null ? companyAttribute.Company : "";

            if (string.IsNullOrEmpty(AppTitle))
            {
                var titleAttribute =
                    (AssemblyTitleAttribute)GetAttribute(mainAssembly, typeof(AssemblyTitleAttribute));
                AppTitle = titleAttribute != null ? titleAttribute.Title : mainAssembly.GetName().Name;
            }

            string registryLocation = !string.IsNullOrEmpty(appCompany)
                ? $@"Software\{appCompany}\{AppTitle}\AutoUpdater"
                : $@"Software\{AppTitle}\AutoUpdater";

            if (PersistenceProvider == null)
            {
                PersistenceProvider = new RegistryPersistenceProvider(registryLocation);
            }

            BaseUri = new Uri(AppCastURL);

            UpdateInfoEventArgs args;

            using (MyWebClient client = GetWebClient(BaseUri, BasicAuthXML))
            {
                string xml = client.DownloadString(BaseUri);

                if (ParseUpdateInfoEvent == null)
                {
                    XmlSerializer xmlSerializer = new XmlSerializer(typeof(UpdateInfoEventArgs));
                    XmlTextReader xmlTextReader = new XmlTextReader(new StringReader(xml))
                    {
                        XmlResolver = null
                    };
                    args = (UpdateInfoEventArgs)xmlSerializer.Deserialize(xmlTextReader);
                }
                else
                {
                    ParseUpdateInfoEventArgs parseArgs = new ParseUpdateInfoEventArgs(xml);
                    ParseUpdateInfoEvent(parseArgs);
                    args = parseArgs.UpdateInfo;
                }
            }

            if (string.IsNullOrEmpty(args.CurrentVersion) || string.IsNullOrEmpty(args.DownloadURL))
            {
                throw new MissingFieldException();
            }

            args.InstalledVersion  = mainAssembly.GetName().Version;
            args.IsUpdateAvailable = new Version(args.CurrentVersion) > mainAssembly.GetName().Version;

            if (!Mandatory)
            {
                if (string.IsNullOrEmpty(args.Mandatory.MinimumVersion) ||
                    args.InstalledVersion < new Version(args.Mandatory.MinimumVersion))
                {
                    Mandatory  = args.Mandatory.Value;
                    UpdateMode = args.Mandatory.UpdateMode;
                }
            }

            if (Mandatory)
            {
                ShowRemindLaterButton = false;
                ShowSkipButton        = false;
            }
            else
            {
                // Read the persisted state from the persistence provider.
                // This method makes the persistence handling independent from the storage method.
                var skippedVersion = PersistenceProvider.GetSkippedVersion();
                if (skippedVersion != null)
                {
                    var currentVersion = new Version(args.CurrentVersion);
                    if (currentVersion <= skippedVersion)
                    {
                        return(null);
                    }

                    if (currentVersion > skippedVersion)
                    {
                        // Update the persisted state. Its no longer makes sense to have this flag set as we are working on a newer application version.
                        PersistenceProvider.SetSkippedVersion(null);
                    }
                }

                var remindLaterAt = PersistenceProvider.GetRemindLater();
                if (remindLaterAt != null)
                {
                    int compareResult = DateTime.Compare(DateTime.Now, remindLaterAt.Value);

                    if (compareResult < 0)
                    {
                        return(remindLaterAt.Value);
                    }
                }
            }

            return(args);
        }