Download RDL files in to pdf file asynchronously,

Question

Download RDL files in to pdf file asynchronously, I have a requirement where I need to download the RDL file to pdf which is working with out any issues. But I have an issue with performance. I have 3 multi select drop down where the first display all the Managers, and on selecting manager corresponding employee will display and on selecting employee I will bind the 3rd one with the list of reports to be converted to RDL.

 

15 reports to be downloaded for each employee selected, let us say if I select 10 employees I need to download 150 reports

 

private async System.Threading.Tasks.Task CreateFolder()
        {
            try
            {
                string reportName = string.Empty;
                string fileName = string.Empty;
                string strPath = string.Empty;
                string strFolderPath = @"c:\My Reports";

                foreach (var manager in manager.SelectedItems)
                {


                    if (employee.SelectedItems.Count > 0)
                    {
                        foreach (var employee in employee.SelectedItems)
                        {
                            if (checkEmployeeManager(employee.Value, manager.Value))
                            {
                                foreach (var report in reportList.SelectedItems)
                                {
                                    SetSelectedReportParameters(report.Key, report.Value);
                                    SetParameterValues(manager.Value.ToString(), "ManagerId");

                                    SetParameterValues(employee.Value.ToString(), "EmployeeId");

                                    strPath = Path.Combine(strFolderPath, manager.Key, employee.Key.Split('-')[0]);
                                    if (!File.Exists(strPath))
                                    {
                                        if (employee.Value != -1)
                                            strPath = strPath + "_" + employee.Key.Split('-')[1];
                                        await System.Threading.Tasks.Task.Run(() => Directory.CreateDirectory(strPath));
                                        if (employee.Value != -1)
                                            fileName = employee.Key.Split('-')[1] + "_" + report.Key + ".pdf";
                                        else
                                            fileName = report.Key.Split('-')[1] + ".pdf";

                                        GenerateReport(strPath, report.Value, fileName);
                                    }
                                }
                            }
                        }
                    }
                }
                var message = string.Format("Report: {0} has been downloaded to the path {1} ", reportName, strPath);
                MessageBox.Show(message, "Success", MessageBoxButton.OK, MessageBoxImage.Information);
            }
            catch (Exception ex)
            {
                var message = string.Format("Encountered an unhandled exception:  {0}", ex.Message);
                MessageBox.Show(message, "Unhandled Exception", MessageBoxButton.OK, MessageBoxImage.Hand);
            }
        }

private void GenerateReport(string DirectoryPath, int ReportId = 0, string fileName = null)
        {
            string expression = "ReportId =" + ReportId;
            DataRow[] selectedRows = reportData.Select(expression);
            string reportName = string.Empty;

            ReportExecutionService rsExec = new ReportExecutionService
            {
                Credentials = new NetworkCredential(),
                Url = "http://mysite/ReportServer/ReportExecution2005.asmx"
            };
            reportName = selectedRows[0]["ReportFileName"].ToString().Replace(".rdl", string.Empty);
            reportName = reportName.Contains("&") ? reportName.Substring(0, reportName.IndexOf("&")) : reportName;
            string fullPath = "/Reports/" + reportName;

            byte[] result = null;
            string reportPath = fullPath;
            string format = "PDF", devInfo = @"<DeviceInfo><Toolbar>True</Toolbar></DeviceInfo>";
            string historyID = null;

            ReportExecution2005.DataSourceCredentials[] credentials = new ReportExecution2005.DataSourceCredentials[1];
            credentials[0] = new ReportExecution2005.DataSourceCredentials
            {
                DataSourceName = myds,
                UserName = userid,
                Password = pwd
            };

            ReportExecution2005.Warning[] warnings = null;
            string[] streamIDs = null;

            ExecutionInfo execInfo = new ExecutionInfo();
            ExecutionHeader execHeader = new ExecutionHeader();

            rsExec.ExecutionHeaderValue = execHeader;


            execInfo = rsExec.LoadReport(reportPath, historyID);
            rsExec.SetExecutionCredentials2(credentials);
            rsExec.SetExecutionParameters2(parms, null);

            try
            {
                result = rsExec.Render(format, devInfo, out string extension, out string encoding, out string mimeType, out warnings, out streamIDs);
                execInfo = rsExec.GetExecutionInfo();
            }
            catch (SoapException e)
            {
                throw new Exception(e.Detail.OuterXml);
            }
            try
            {
                fileName = String.Join(string.Empty, fileName.Split(Path.GetInvalidFileNameChars()));
                File.WriteAllBytes(Path.Combine(DirectoryPath, fileName), result);
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }

I am calling the button click event asynchronously and calling create folder, looking for better code which improves performance 

private async void btnReport_Click(object sender, RoutedEventArgs e)
        {
            await CreateFolder();
        }