C# Discussion Boards - CodeProject

Gerry Schmitz23-Mar-17 17:38

Gerry Schmitz

23-Mar-17 17:38

x is 11 because you're writing to the console AFTER x was incremented. You would see x = 10 if you had coded as follows:

int x = 10;
Console.WriteLine(x);   // Displays 10.
int y = x++;
Console.WriteLine(x);   // Displays 11.
etc.

"(I) am amazed to see myself here rather than there ... now rather than then".
― Blaise Pascal

V.23-Mar-17 20:19

23-Mar-17 20:19

As you can tell from the responses the line:

int y = x++;

is pretty confusing. I would try to avoid such prefix/postfix with assignements except for constructs like for loops or while loops.

for(int x = 0; x < somelength; x++){
   //code
}

//or

int x = 0;
while(x < somelength){
    //code
    x++;
}

hope this helps.

(MQOTD rules and previous solutions)

Richard MacCutchan23-Mar-17 22:43

Richard MacCutchan

23-Mar-17 22:43

V. wrote:
is pretty confusing.

I have never found that to be so, even back in 1987 when I first read The C Programming Language[^].

messagebox problem when process completed

OriginalGriff23-Mar-17 23:36

OriginalGriff

23-Mar-17 23:36

Just to add to the other responses, try to keep pre- and post-fix autoincrement and autodecrement operations to simple code:

for (int i = 0; i < 10; i++)

do 
   {
   Console.WriteLine(myArray[i]);
   ...
   } while (myArray[i++] > 0)

They are easy to understand, and every developer with more than a few weeks experience should be able to understand that at a glance.
Don't get "creative" with it:

x = (x++ + --x);

Is confusing and not at all obvious what the result will be. In C# it's defined by the language specification (but still hard to read) - in similar looking languages like C and C++ it isn't, and different compilers will produce different results (heck, even different versions of the same compiler or different optimisation options can produce different results!)
Keep it simple, and it's a powerful tool which makes code more compact and easier to read: Compilcate it, and things get confusing very quickly!

Bad command or file name. Bad, bad command! Sit! Stay! Staaaay...

Akshit.b23-Mar-17 0:17

Akshit.b

23-Mar-17 0:17

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
//using System.Threading.Tasks;
using System.Windows.Forms;
using System.Diagnostics;
using System.IO;
using System.Management;
using System.Reflection;
using System.Threading;
using System.Configuration;
using System.Net;
using System.Net.NetworkInformation;


namespace RemoteBlocker
{
    public partial class Form2 : Form
    {
        BackgroundWorker bgw = new BackgroundWorker();

        int mode = 0;

        public Form2()
        {
            InitializeComponent();
        }

        private void bgw_DoWork(object sender, DoWorkEventArgs e)
        {
            int total = 100;

            for (int i = 0; i <= total; i++)
            {
                System.Threading.Thread.Sleep(50);
                int percents = (i * 100) / total;
                bgw.ReportProgress(percents, i);
            }
        }

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

        private void bgw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            //do the code when bgv completes its work
            progressBar1.Visible = false;

            if (mode == 1)
            {
                MessageBox.Show("Enable Successfully.");
            }
            else if (mode == 2)
            {
                MessageBox.Show("Disable Successfully.");
            }           
        }

        private void btnDisable_Click(object sender, EventArgs e)
        {
            try
            {
                Ping pingServer1 = new Ping();
                PingReply pingresultFrmServer1 = pingServer1.Send("172.16.102.4");
                if (pingresultFrmServer1.Status.ToString() == "Success")
                {
                    try
                    {
                        Process proc = null;

                        string batDir = System.Configuration.ConfigurationManager.AppSettings["block1"];
                        string executebatDir = System.Configuration.ConfigurationManager.AppSettings["executeblock"];

                        FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(batDir);
                        ftpRequest.Credentials = new NetworkCredential("subhankar", "subhankar");
                        ftpRequest.Method = WebRequestMethods.Ftp.ListDirectory;
                        FtpWebResponse response = (FtpWebResponse)ftpRequest.GetResponse();

                        StreamReader streamReader = new StreamReader(response.GetResponseStream());
                        List<string> directories = new List<string>();

                        string line = streamReader.ReadLine();
                        while (!string.IsNullOrEmpty(line))
                        {
                            directories.Add(line);
                            line = streamReader.ReadLine();
                        }
                        streamReader.Close();

                        using (WebClient ftpClient = new WebClient())
                        {
                            ftpClient.Credentials = new System.Net.NetworkCredential("subhankar", "subhankar");

                            for (int i = 0; i <= directories.Count - 1; i++)
                            {
                                if (directories[i].Contains("."))
                                {
                                    string path = batDir + directories[i].ToString();
                                    string trnsfrpth = executebatDir + directories[i].ToString();
                                    ftpClient.DownloadFile(path, trnsfrpth);
                                }
                            }

                            proc = new Process();

                            string trnsfrexepth = executebatDir;
                            proc.StartInfo.WorkingDirectory = trnsfrexepth;

                            proc.StartInfo.FileName = "Hostblock.bat";
                            proc.StartInfo.CreateNoWindow = false;
                            proc.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
                            proc.StartInfo.Verb = "runas";
                            proc.Start();
                            proc.WaitForExit();

                            // Delete From temp folder

                            DirectoryInfo dir = new DirectoryInfo(trnsfrexepth);

                            foreach (FileInfo files in dir.GetFiles("*.bat"))
                            {
                                files.Delete();
                            }

                            foreach (DirectoryInfo dirs in dir.GetDirectories())
                            {
                                //dirs.Delete(true);
                            }

                            progressBar1.Visible = true;

                            bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);
                            bgw.ProgressChanged += new ProgressChangedEventHandler(bgw_ProgressChanged);
                            bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);
                            bgw.WorkerReportsProgress = true;
                            bgw.RunWorkerAsync();

                            mode = 1;                            
                        }
                    }
                    catch (Exception exc)
                    {

                    }
                    finally
                    {

                    }
                }
                else
                {
                    Ping pingServer2 = new Ping();
                    PingReply pingresultFrmServer2 = pingServer2.Send("172.16.102.4");
                    if (pingresultFrmServer2.Status.ToString() == "Success")
                    {
                        try
                        {
                            Process proc = null;

                            string batDir = System.Configuration.ConfigurationManager.AppSettings["block2"];
                            string executebatDir = System.Configuration.ConfigurationManager.AppSettings["executeblock"];

                            FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(batDir);
                            ftpRequest.Credentials = new NetworkCredential("subhankar", "subhankar");
                            ftpRequest.Method = WebRequestMethods.Ftp.ListDirectory;
                            FtpWebResponse response = (FtpWebResponse)ftpRequest.GetResponse();

                            StreamReader streamReader = new StreamReader(response.GetResponseStream());
                            List<string> directories = new List<string>();

                            string line = streamReader.ReadLine();
                            while (!string.IsNullOrEmpty(line))
                            {
                                directories.Add(line);
                                line = streamReader.ReadLine();
                            }
                            streamReader.Close();

                            using (WebClient ftpClient = new WebClient())
                            {
                                ftpClient.Credentials = new System.Net.NetworkCredential("subhankar", "subhankar");

                                for (int i = 0; i <= directories.Count - 1; i++)
                                {
                                    if (directories[i].Contains("."))
                                    {
                                        string path = batDir + directories[i].ToString();
                                        string trnsfrpth = executebatDir + directories[i].ToString();
                                        ftpClient.DownloadFile(path, trnsfrpth);
                                    }
                                }

                                proc = new Process();

                                string trnsfrexepth = executebatDir;
                                proc.StartInfo.WorkingDirectory = trnsfrexepth;

                                proc.StartInfo.FileName = "Hostblock.bat";
                                proc.StartInfo.CreateNoWindow = false;
                                proc.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
                                proc.StartInfo.Verb = "runas";
                                proc.Start();
                                proc.WaitForExit();

                                // Delete From temp folder

                                DirectoryInfo dir = new DirectoryInfo(trnsfrexepth);

                                foreach (FileInfo files in dir.GetFiles("*.bat"))
                                {
                                    files.Delete();
                                }

                                foreach (DirectoryInfo dirs in dir.GetDirectories())
                                {
                                    //dirs.Delete(true);
                                }

                                progressBar1.Visible = true;

                                //bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);
                                //bgw.ProgressChanged += new ProgressChangedEventHandler(bgw_ProgressChanged);
                                //bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);
                                //bgw.WorkerReportsProgress = true;
                                bgw.RunWorkerAsync();

                                mode = 1;
                            }
                        }
                        catch (Exception exc)
                        {

                        }
                        finally
                        {

                        }
                    }
                    else
                    {
                        Ping pingServer3 = new Ping();
                        PingReply pingresultFrmServer3 = pingServer3.Send("172.16.102.4");
                        if (pingresultFrmServer3.Status.ToString() == "Success")
                        {
                            try
                            {
                                Process proc = null;

                                string batDir = System.Configuration.ConfigurationManager.AppSettings["block3"];
                                string executebatDir = System.Configuration.ConfigurationManager.AppSettings["executeblock"];

                                FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(batDir);
                                ftpRequest.Credentials = new NetworkCredential("subhankar", "subhankar");
                                ftpRequest.Method = WebRequestMethods.Ftp.ListDirectory;
                                FtpWebResponse response = (FtpWebResponse)ftpRequest.GetResponse();

                                StreamReader streamReader = new StreamReader(response.GetResponseStream());
                                List<string> directories = new List<string>();

                                string line = streamReader.ReadLine();
                                while (!string.IsNullOrEmpty(line))
                                {
                                    directories.Add(line);
                                    line = streamReader.ReadLine();
                                }
                                streamReader.Close();

                                using (WebClient ftpClient = new WebClient())
                                {
                                    ftpClient.Credentials = new System.Net.NetworkCredential("subhankar", "subhankar");

                                    for (int i = 0; i <= directories.Count - 1; i++)
                                    {
                                        if (directories[i].Contains("."))
                                        {
                                            string path = batDir + directories[i].ToString();
                                            string trnsfrpth = executebatDir + directories[i].ToString();
                                            ftpClient.DownloadFile(path, trnsfrpth);
                                        }
                                    }

                                    proc = new Process();

                                    string trnsfrexepth = executebatDir;
                                    proc.StartInfo.WorkingDirectory = trnsfrexepth;

                                    proc.StartInfo.FileName = "Hostblock.bat";
                                    proc.StartInfo.CreateNoWindow = false;
                                    proc.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
                                    proc.StartInfo.Verb = "runas";
                                    proc.Start();
                                    proc.WaitForExit();

                                    // Delete From temp folder

                                    DirectoryInfo dir = new DirectoryInfo(trnsfrexepth);

                                    foreach (FileInfo files in dir.GetFiles("*.bat"))
                                    {
                                        files.Delete();
                                    }

                                    foreach (DirectoryInfo dirs in dir.GetDirectories())
                                    {
                                        //dirs.Delete(true);
                                    }

                                    progressBar1.Visible = true;

                                    //bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);
                                    //bgw.ProgressChanged += new ProgressChangedEventHandler(bgw_ProgressChanged);
                                    //bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);
                                    //bgw.WorkerReportsProgress = true;
                                    bgw.RunWorkerAsync();

                                    mode = 1;
                                }
                            }
                            catch (Exception exc)
                            {

                            }
                            finally
                            {

                            }

                        }
                    }





                    //////////////////////////////////////////////////////////////////////////

                    //Process proc = null;

                    //string batDir = System.Configuration.ConfigurationManager.AppSettings["block1"];
                    //string executebatDir = System.Configuration.ConfigurationManager.AppSettings["executeblock"];

                    //FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(batDir);
                    //ftpRequest.Credentials = new NetworkCredential("subhankar", "subhankar");
                    //ftpRequest.Method = WebRequestMethods.Ftp.ListDirectory;
                    //FtpWebResponse response = (FtpWebResponse)ftpRequest.GetResponse();

                    //StreamReader streamReader = new StreamReader(response.GetResponseStream());
                    //List<string> directories = new List<string>();

                    //string line = streamReader.ReadLine();
                    //while (!string.IsNullOrEmpty(line))
                    //{
                    //    directories.Add(line);
                    //    line = streamReader.ReadLine();
                    //}
                    //streamReader.Close();

                    //using (WebClient ftpClient = new WebClient())
                    //{
                    //    ftpClient.Credentials = new System.Net.NetworkCredential("subhankar", "subhankar");

                    //    for (int i = 0; i <= directories.Count - 1; i++)
                    //    {
                    //        if (directories[i].Contains("."))
                    //        {
                    //            string path = batDir + directories[i].ToString();
                    //            string trnsfrpth = executebatDir + directories[i].ToString();
                    //            ftpClient.DownloadFile(path, trnsfrpth);
                    //        }
                    //    }

                    //    proc = new Process();

                    //    string trnsfrexepth = executebatDir;
                    //    proc.StartInfo.WorkingDirectory = trnsfrexepth;

                    //    proc.StartInfo.FileName = "Hostblock.bat";
                    //    proc.StartInfo.CreateNoWindow = false;
                    //    proc.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
                    //    proc.StartInfo.Verb = "runas";
                    //    proc.Start();
                    //    proc.WaitForExit();

                    //    // Delete From temp folder

                    //    DirectoryInfo dir = new DirectoryInfo(trnsfrexepth);

                    //    foreach (FileInfo files in dir.GetFiles("*.bat"))
                    //    {
                    //        files.Delete();
                    //    }

                    //    foreach (DirectoryInfo dirs in dir.GetDirectories())
                    //    {
                    //        //dirs.Delete(true);
                    //    }

                    //    progressBar1.Visible = true;

                    //    bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);
                    //    bgw.ProgressChanged += new ProgressChangedEventHandler(bgw_ProgressChanged);
                    //    bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);
                    //    bgw.WorkerReportsProgress = true;
                    //    bgw.RunWorkerAsync();

                    //    mode = 1;
                    //}
                }
            }
            catch (Exception exc)
            {
                MessageBox.Show(exc.ToString());
            }
        }

        private void btnEnable_Click(object sender, EventArgs e)
        {
            try
            {
                Ping pingServer1 = new Ping();
                PingReply pingresultFrmServer1 = pingServer1.Send("172.16.102.4");
                if (pingresultFrmServer1.Status.ToString() == "Success")
                {
                    try 
                    {
                        Process proc = null;

                        string batDir = System.Configuration.ConfigurationManager.AppSettings["unblock1"];
                        string executebatDir = System.Configuration.ConfigurationManager.AppSettings["executeunblock"];

                        FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(batDir);
                        ftpRequest.Credentials = new NetworkCredential("subhankar", "subhankar");
                        ftpRequest.Method = WebRequestMethods.Ftp.ListDirectory;
                        FtpWebResponse response = (FtpWebResponse)ftpRequest.GetResponse();
                        StreamReader streamReader = new StreamReader(response.GetResponseStream());
                        List<string> directories = new List<string>();

                        string line = streamReader.ReadLine();
                        while (!string.IsNullOrEmpty(line))
                        {
                            directories.Add(line);
                            line = streamReader.ReadLine();
                        }
                        streamReader.Close();

                        using (WebClient ftpClient = new WebClient())
                        {
                            ftpClient.Credentials = new System.Net.NetworkCredential("subhankar", "subhankar");

                            for (int i = 0; i <= directories.Count - 1; i++)
                            {
                                if (directories[i].Contains("."))
                                {
                                    string path = batDir + directories[i].ToString();
                                    string trnsfrpth = executebatDir + directories[i].ToString();
                                    ftpClient.DownloadFile(path, trnsfrpth);
                                }
                            }

                            proc = new Process();

                            string trnsfrexepth = executebatDir;
                            proc.StartInfo.WorkingDirectory = trnsfrexepth;

                            proc.StartInfo.FileName = "Undohostblock.bat";
                            proc.StartInfo.CreateNoWindow = false;
                            proc.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Normal;
                            proc.StartInfo.Verb = "runas";
                            proc.Start();
                            proc.WaitForExit();

                            // Delete From temp folder

                            DirectoryInfo dir = new DirectoryInfo(trnsfrexepth);

                            foreach (FileInfo files in dir.GetFiles("*.bat"))
                            {
                                files.Delete();
                            }

                            foreach (DirectoryInfo dirs in dir.GetDirectories())
                            {
                                //dirs.Delete(true);
                            }

                            progressBar1.Visible = true;

                            bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);
                            bgw.ProgressChanged += new ProgressChangedEventHandler(bgw_ProgressChanged);
                            bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);
                            bgw.WorkerReportsProgress = true;
                            bgw.RunWorkerAsync();
                            
                            mode = 2;
                        } 
                    }
                    catch(Exception exc)
                    {
                        
                    }
                    finally
                    {

                    }
                }
                else 
                {
                    Ping pingServer2 = new Ping();
                    PingReply pingresultFrmServer2 = pingServer2.Send("172.16.102.4");
                    if (pingresultFrmServer2.Status.ToString() == "Success")
                    {
                        try
                        {
                            Process proc = null;

                            string batDir = System.Configuration.ConfigurationManager.AppSettings["unblock2"];
                            string executebatDir = System.Configuration.ConfigurationManager.AppSettings["executeunblock"];

                            FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(batDir);
                            ftpRequest.Credentials = new NetworkCredential("subhankar", "subhankar");
                            ftpRequest.Method = WebRequestMethods.Ftp.ListDirectory;
                            FtpWebResponse response = (FtpWebResponse)ftpRequest.GetResponse();
                            StreamReader streamReader = new StreamReader(response.GetResponseStream());
                            List<string> directories = new List<string>();

                            string line = streamReader.ReadLine();
                            while (!string.IsNullOrEmpty(line))
                            {
                                directories.Add(line);
                                line = streamReader.ReadLine();
                            }
                            streamReader.Close();

                            using (WebClient ftpClient = new WebClient())
                            {
                                ftpClient.Credentials = new System.Net.NetworkCredential("subhankar", "subhankar");

                                for (int i = 0; i <= directories.Count - 1; i++)
                                {
                                    if (directories[i].Contains("."))
                                    {
                                        string path = batDir + directories[i].ToString();
                                        string trnsfrpth = executebatDir + directories[i].ToString();
                                        ftpClient.DownloadFile(path, trnsfrpth);
                                    }
                                }

                                proc = new Process();

                                string trnsfrexepth = executebatDir;
                                proc.StartInfo.WorkingDirectory = trnsfrexepth;

                                proc.StartInfo.FileName = "Undohostblock.bat";
                                proc.StartInfo.CreateNoWindow = false;
                                proc.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Normal;
                                proc.StartInfo.Verb = "runas";
                                proc.Start();
                                proc.WaitForExit();

                                // Delete From temp folder

                                DirectoryInfo dir = new DirectoryInfo(trnsfrexepth);

                                foreach (FileInfo files in dir.GetFiles("*.bat"))
                                {
                                    files.Delete();
                                }

                                foreach (DirectoryInfo dirs in dir.GetDirectories())
                                {
                                    //dirs.Delete(true);
                                }

                                progressBar1.Visible = true;

                                //bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);
                                //bgw.ProgressChanged += new ProgressChangedEventHandler(bgw_ProgressChanged);
                                //bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);
                                //bgw.WorkerReportsProgress = true;
                                bgw.RunWorkerAsync();

                                mode = 2;
                            } 
                        }
                        catch (Exception exc)
                        {

                        }
                        finally
                        {

                        }
                    }
                    else
                    {
                        Ping pingServer3 = new Ping();
                        PingReply pingresultFrmServer3 = pingServer3.Send("172.16.102.4");
                        if (pingresultFrmServer3.Status.ToString() == "Success")
                        {
                            try
                            {
                                Process proc = null;

                                string batDir = System.Configuration.ConfigurationManager.AppSettings["unblock3"];
                                string executebatDir = System.Configuration.ConfigurationManager.AppSettings["executeunblock"];

                                FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(batDir);
                                ftpRequest.Credentials = new NetworkCredential("subhankar", "subhankar");
                                ftpRequest.Method = WebRequestMethods.Ftp.ListDirectory;
                                FtpWebResponse response = (FtpWebResponse)ftpRequest.GetResponse();
                                StreamReader streamReader = new StreamReader(response.GetResponseStream());
                                List<string> directories = new List<string>();

                                string line = streamReader.ReadLine();
                                while (!string.IsNullOrEmpty(line))
                                {
                                    directories.Add(line);
                                    line = streamReader.ReadLine();
                                }
                                streamReader.Close();

                                using (WebClient ftpClient = new WebClient())
                                {
                                    ftpClient.Credentials = new System.Net.NetworkCredential("subhankar", "subhankar");

                                    for (int i = 0; i <= directories.Count - 1; i++)
                                    {
                                        if (directories[i].Contains("."))
                                        {
                                            string path = batDir + directories[i].ToString();
                                            string trnsfrpth = executebatDir + directories[i].ToString();
                                            ftpClient.DownloadFile(path, trnsfrpth);
                                        }
                                    }

                                    proc = new Process();

                                    string trnsfrexepth = executebatDir;
                                    proc.StartInfo.WorkingDirectory = trnsfrexepth;

                                    proc.StartInfo.FileName = "Undohostblock.bat";
                                    proc.StartInfo.CreateNoWindow = false;
                                    proc.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Normal;
                                    proc.StartInfo.Verb = "runas";
                                    proc.Start();
                                    proc.WaitForExit();

                                    // Delete From temp folder

                                    DirectoryInfo dir = new DirectoryInfo(trnsfrexepth);

                                    foreach (FileInfo files in dir.GetFiles("*.bat"))
                                    {
                                        files.Delete();
                                    }

                                    foreach (DirectoryInfo dirs in dir.GetDirectories())
                                    {
                                        //dirs.Delete(true);
                                    }

                                    progressBar1.Visible = true;

                                    //bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);
                                    //bgw.ProgressChanged += new ProgressChangedEventHandler(bgw_ProgressChanged);
                                    //bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);
                                    //bgw.WorkerReportsProgress = true;
                                    bgw.RunWorkerAsync();

                                    mode = 2;
                                }
                            }
                            catch (Exception exc)
                            {

                            }
                            finally
                            {

                            }
                        }
                        else
                        {

                        }
                    }
                }

                //////////////////////////////////////////////////////

                //Process proc = null;

                //string batDir = System.Configuration.ConfigurationManager.AppSettings["unblock1"];
                //string executebatDir = System.Configuration.ConfigurationManager.AppSettings["executeunblock"];

                //FtpWebRequest ftpRequest = (FtpWebRequest)WebRequest.Create(batDir);
                //ftpRequest.Credentials = new NetworkCredential("subhankar", "subhankar");
                //ftpRequest.Method = WebRequestMethods.Ftp.ListDirectory;
                //FtpWebResponse response = (FtpWebResponse)ftpRequest.GetResponse();
                //StreamReader streamReader = new StreamReader(response.GetResponseStream());
                //List<string> directories = new List<string>();

                //string line = streamReader.ReadLine();
                //while (!string.IsNullOrEmpty(line))
                //{
                //    directories.Add(line);
                //    line = streamReader.ReadLine();
                //}
                //streamReader.Close();

                //using (WebClient ftpClient = new WebClient())
                //{
                //    ftpClient.Credentials = new System.Net.NetworkCredential("subhankar", "subhankar");

                //    for (int i = 0; i <= directories.Count - 1; i++)
                //    {
                //        if (directories[i].Contains("."))
                //        {
                //            string path = batDir + directories[i].ToString();
                //            string trnsfrpth = executebatDir + directories[i].ToString();
                //            ftpClient.DownloadFile(path, trnsfrpth);
                //        }
                //    }

                //    proc = new Process();

                //    string trnsfrexepth = executebatDir;
                //    proc.StartInfo.WorkingDirectory = trnsfrexepth;

                //    proc.StartInfo.FileName = "Undohostblock.bat";
                //    proc.StartInfo.CreateNoWindow = false;
                //    proc.StartInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Normal;
                //    proc.StartInfo.Verb = "runas";
                //    proc.Start();
                //    proc.WaitForExit();

                //    // Delete From temp folder

                //    DirectoryInfo dir = new DirectoryInfo(trnsfrexepth);

                //    foreach (FileInfo files in dir.GetFiles("*.bat"))
                //    {
                //        files.Delete();
                //    }

                //    foreach (DirectoryInfo dirs in dir.GetDirectories())
                //    {
                //        //dirs.Delete(true);
                //    }                                    

                //    progressBar1.Visible = true;

                //    bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);
                //    bgw.ProgressChanged += new ProgressChangedEventHandler(bgw_ProgressChanged);
                //    bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);
                //    bgw.WorkerReportsProgress = true;
                //    bgw.RunWorkerAsync();

                //    mode = 2;
                //}                
            }
            catch (Exception exc)
            {
                MessageBox.Show(exc.ToString());
            }
        }

        private void btnClose_Click(object sender, EventArgs e)
        {
            Form2 f = new Form2();
            this.Hide();
            f.Close();
        }

        private void btnAdmin_Click(object sender, EventArgs e)
        {
            Form3 f = new Form3();
            this.Hide();
            f.Show();
        }       
    }
}

after clicking enable button when clicking disable button then message box comes 2 times.it is increasing recursively.

Richard MacCutchan23-Mar-17 2:08

Richard MacCutchan

23-Mar-17 2:08

Please edit your question and remove all the code not relevant to the problem, and show exactly where the problem occurs.

Dave Kreskowiak23-Mar-17 2:43

Dave Kreskowiak

23-Mar-17 2:43

Yeah, nobody is going to dig through all that code. Reduce it down to just the necessary parts and someone might take a look at it.

A guide to posting questions on CodeProject

Click this: Asking questions is a skill.
Seriously, do it.

Dave Kreskowiak

Gerry Schmitz23-Mar-17 17:41

Gerry Schmitz

23-Mar-17 17:41

More paragraphs! (i.e. "Methods").

"(I) am amazed to see myself here rather than there ... now rather than then".
― Blaise Pascal

Luc Pattyn24-Mar-17 4:27

Luc Pattyn

24-Mar-17 4:27

Hi,

you seem to create one BackgroundWorker and reuse it over and over. Be aware that each time you execute a line such as

bgw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);

you ADD a handler to the event, so the second time the event fires, it will execute the same handler twice.
As this also applies to your line

bgw.DoWork += new DoWorkEventHandler(bgw_DoWork);

I expect your BGW will duplicate its work and the number of results will behave quadratically.

There are several remedies:
1) you could remove the handlers with similar lines, say

bgw.RunWorkerCompleted -= new RunWorkerCompletedEventHandler(bgw_RunWorkerCompleted);

2) you could create a new BackgroundWorker each time;
3) but why not stuff all the work inside the bgw_DoWork method, and run the BackgroundWorker only once?

Smile | :)

Luc Pattyn [My Articles] Nil Volentibus Arduum

modified 24-Mar-17 10:37am.

How to write a generic code to make async call to Rest Service

Akshit.b26-Mar-17 20:22

Akshit.b

26-Mar-17 20:22

Thanks... it is working

ArunHanu22-Mar-17 0:31

ArunHanu

22-Mar-17 0:31

I am creating a Xamarin app and I have to populate master data into sqlite DB on mobile.

I am new to OOPS and Xamarin

I have multiple requests to be made to get data from WebApi. The request I need to make is more than 50 calls to get info.

Now, I need to write async generic code to achieve this.

For example: I have to populate data for EmployeeMaster, Company Master etc..

My generic code should be able to identify which URL to call and Which object has to be returned. My normal code is as follows below

The only varying data are RestUrl and TodoItem

public async Task<list<todoitem>> RefreshDataAsync ()
{
Items = new List<todoitem> ();
RestUrl = "http://localhost:9054/TotoItem"
var uri = new Uri (string.Format (RestUrl, string.Empty));

try {
var response = await client.GetAsync (uri);
if (response.IsSuccessStatusCode) {
var content = await response.Content.ReadAsStringAsync ();
Items = JsonConvert.DeserializeObject <list<todoitem>> (content);
}
} catch (Exception ex) {
Debug.WriteLine (@" ERROR {0}", ex.Message);
}

return Items;
}

Re: How to write a generic code to make async call to Rest Service

Nathan Minier22-Mar-17 1:13

Re: How to write a generic code to make async call to Rest Service

22-Mar-17 1:13

Well, you're returning List<todoitem>, which is different from Task<list<todoitem>>.

It's also worth noting that your method, as written, will run synchronously despite your *Async() naming.

Convert the return type to List<todoitem> and rename your function and see what happens.

You likely also want to define variables in the method scope for Items and RestUrl. You also appear to have a typo in a string constant. Check the RestUrl variable.

"There are three kinds of lies: lies, damned lies and statistics."
- Benjamin Disraeli

ArunHanu22-Mar-17 1:43

ArunHanu

22-Mar-17 1:43

Thank you Benjamin,

Even making the change will create a strong bond with todoitem. My intention is to make it generalised so that I can make a single method for making calls for different URL's and get data for different class object

As I have stated earlier I don't want to write the same code for a different URL request.

Re: How to write a generic code to make async call to Rest Service

Pete O'Hanlon22-Mar-17 2:03

Pete O'Hanlon

22-Mar-17 2:03

I tackled an issue similar to this a couple of years ago when I wrote, first this[^] article and then it's follow up here[^]. The architecture is a little bit convoluted so please take the time to read it and the code in the project files carefully.

This space for rent

Re: How to write a generic code to make async call to Rest Service

Nathan Minier22-Mar-17 2:08

Re: How to write a generic code to make async call to Rest Service

22-Mar-17 2:08

Not a Benjamin, that's a quote.

You need to tack down the real basic fundamentals first; generics in C# are first class members and almost trivial.

But if you'd rather walk before crawling:

public async T RefreshData<T>(string url)
{
   try 
   {
      var response = await client.GetAsync (url);
      if (response.IsSuccessStatusCode) {
         var content = await response.Content.ReadAsStringAsync ();
         var items = JsonConvert.DeserializeObject<T>(content);
         if(items != null)
         {
            return items;
         }
         throw new Exception($"Service did not provide a response formatted as type: {typeof(T)}");
      }else{
         throw new Exception($"Service request failure. Code: {response.StatusCode}");
      }
   } 
   catch (Exception ex) 
   {
      Debug.WriteLine ($"ERROR {ex.Message}");
   }
}

The $"" is the newfangled string interpolation BTW. Call with:

var myList = RefreshData<List<todoitem>>("http ://localhost:9054/TotoItem");

I had to throw an extra space in the string as the C# preformat is throwing in an anchor tag.

"There are three kinds of lies: lies, damned lies and statistics."
- Benjamin Disraeli

Richard Deeming22-Mar-17 2:23

Re: How to write a generic code to make async call to Rest Service

22-Mar-17 2:23

Nathan Minier wrote:
you're returning List<todoitem>, which is different from Task<List<todoitem>>.

It's an async method, so that's perfectly normal. Smile | :)

Nathan Minier wrote:
your method, as written, will run synchronously

Nope:

var response = await client.GetAsync (uri);

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

ArunHanu22-Mar-17 3:06

ArunHanu

22-Mar-17 3:06

Thanks a lot Nathan Minier and Richard Deeming for the solution.

I will try to implement same solution and check

Re: How to write a generic code to make async call to Rest Service

Nathan Minier22-Mar-17 3:53

Re: How to write a generic code to make async call to Rest Service

22-Mar-17 3:53

I'm sorry Richard, that's not correct.

Using the async keyword can mean that you want to return a Task that is not yet resolved, but doesn't necessarily mean that. It can simply mean that you're coalescing an asynchronous operation into a synchronous context, which is precisely what "await" does.

Using the await keyword means that you want to use the value provided by Task.Result, not the Task itself. It blocks execution of the method (ie runs synchronously) until the awaited Task is completed. That means that while the method is flagged as async, it resolves async operations into a synchronous context. I understand that the terminology is a bit misleading and the documentation does not help. But the fact is that if you're blocking the thread, you are running synchronously.

If the method were run asynchronously, it would look more like this:

public async Task<T> RefreshData<T>(string url)
{
   return Task<T>.Run(()=>
   {
      var response = await client.GetAsync (url);
      if (response.IsSuccessStatusCode) {
         var content = await response.Content.ReadAsStringAsync ();
         var items = JsonConvert.DeserializeObject<T>(content);
         if(items != null)
         {
            return items;
         }
         throw new Exception($"Service did not provide a response formatted as type: {typeof(T)}");
      }else{
         throw new Exception($"Service request failure. Code: {response.StatusCode}");
      }
   })
   .ContinueWith(ex => { Debug.WriteLine ($"ERROR {ex.Message}");}, TaskContinuationOptions.OnlyOnFaulted));
}

I just didn't want to confuse the poor guy with Task execution and moving between synchronous and asynchronous contexts when he doesn't even have generics down.

"There are three kinds of lies: lies, damned lies and statistics."
- Benjamin Disraeli

Richard Deeming22-Mar-17 4:20

Re: How to write a generic code to make async call to Rest Service

22-Mar-17 4:20

No, sorry, that's not correct.

The await client.GetAsync(url) and await response.Content.ReadAsStringAsync() calls will not block the current thread. They will sign up the rest of the method as a continuation, which will be invoked when the returned Task<T> has completed.

The GetAsync and ReadAsStringAsync calls (eventually) use an IO completion port to receive notification when the request has completed.

That's the whole point of async / await. Smile | :)

The only thing your example is doing differently is that it's using a background thread to run the very first part of the method - the call to GetAsync. As a result, the rest of the method will not run on the captured execution context from the caller of RefreshData. But you could achieve the same result by adding .ConfigureAwait(false) to the end of the GetAsync and ReadAsStringAsync calls.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Nathan Minier22-Mar-17 4:59

Re: How to write a generic code to make async call to Rest Service

22-Mar-17 4:59

I was completely lazy with that sample and I accept that, but it was just to illustrate a point. I think the issue we're having is that we're discussing different contexts.

I'm talking about the code that I'm looking at. I can't see the calling code, so am therefore not addressing it, and that's the code you're talking about. I realize that internal conventions are not the same as generally accepted practice, and my point about the return type and naming convention was not relevant, so I accept proper chastisement there.

I think we can both agree that the code we're looking at, and just that code, will not behave in an asynchronous manner.

"There are three kinds of lies: lies, damned lies and statistics."
- Benjamin Disraeli

Richard Deeming22-Mar-17 5:26

Re: How to write a generic code to make async call to Rest Service

22-Mar-17 5:26

But that's the point - it WILL behave in an asynchronous manner! Smile | :)

public async Task<List<todoitem>> RefreshDataAsync ()
{
    Items = new List<todoitem> ();
    RestUrl = "http://localhost:9054/TotoItem"
    var uri = new Uri (string.Format (RestUrl, string.Empty));
    
    try {
        // Runs synchronously up to here...
        var response = await client.GetAsync (uri);
        
        // The rest of the method is signed up as a continuation,
        // invoked when the IO completion port notifies that the request has been completed.
        // The current thread is NOT blocked.
        
        // Depending on the calling context, the continuation MIGHT run on the same thread as the caller.
        // But this is handled asynchronously; the thread does not block waiting to run the continuation.
        // This can be changed by adding ".ConfigureAwait(false)" after "GetAsync(url)".
        
        if (response.IsSuccessStatusCode) {
            var content = await response.Content.ReadAsStringAsync ();
            // Again, the rest of the method is signed up as a continuation.
            // The thread is NOT blocked waiting for the response content to be downloaded.
            
            Items = JsonConvert.DeserializeObject <List<todoitem>> (content);
            // The JSON conversion IS run syncronously.
            // But async support in JSON.NET was only recently added (v10.1), so there's probably no option here.
    }
    } catch (Exception ex) {
        Debug.WriteLine (@" ERROR {0}", ex.Message);
    }
    
    return Items;
}

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Nathan Minier22-Mar-17 6:06

Re: How to write a generic code to make async call to Rest Service

22-Mar-17 6:06

var response = await client.GetAsync (uri);<br />
// Code execution within this method halted until response is resolved
if (response.IsSuccessStatusCode) {

This is an synchronous pattern within the context of the method, which is the only code that we see. No other actions will be taken by the available code until this resolves. The lack of thread blocking is not the point, the code execution flow in the method is the same as if the thread were blocked.

The Task continuation is only of interest to the calling code so that it can treat it appropriately.

"There are three kinds of lies: lies, damned lies and statistics."
- Benjamin Disraeli

Richard Deeming22-Mar-17 6:16

Re: How to write a generic code to make async call to Rest Service

22-Mar-17 6:16

The same argument applies to your "asynchronous" version:

public async Task<T> RefreshData<T>(string url)
{
   return Task<T>.Run(()=>
   {
      var response = await client.GetAsync (url);
      // Code execution within this method halted until response is resolved
      ...
   })
   .ContinueWith(ex => { Debug.WriteLine ($"ERROR {ex.Message}");}, TaskContinuationOptions.OnlyOnFaulted));
}

You've just moved the "logically synchronous" part to a lambda method, at the expense of making the outer method more complicated. Smile | :)

Adding the *Async suffix to a task-returning method is the recommended naming convention. Adding an extra Task.Run for extra asynchronicity doesn't really achieve anything. It's only going to have any effect if your method has with a long-running synchronous block before the first await call, and Task.Yield would probably be a better solution for that.

"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer

Nathan Minier23-Mar-17 1:12