Windows service with sql [closed]

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partial class TestService : ServiceBase
{
   FileStream fs;
   StreamWriter sw;

   public TestService()
   {
        InitializeComponent();
        fs = new FileStream(@"C:\SampleLast.txt", FileMode.Create);
        sw = new StreamWriter(fs);
    }

    protected override void OnStart(string[] args)
    {
        try
        {
            if (!File.Exists(@"C:\SampleLast.txt"))
            {
                  fs = new FileStream(@"C:\SampleLast.txt", FileMode.Create);
                  sw = new StreamWriter(fs);
            }

            sw.WriteLine("Service start {0}", DateTime.Now.ToString());

            Timer timerNew = new Timer();
            timerNew.Elapsed += new ElapsedEventHandler(timerNew_Elapsed);
            timerNew.Enabled = true;
            timerNew.Interval = 4000;
            timerNew.Start();

            sw.WriteLine(timerNew.Enabled.ToString());
            sw.Flush();
        }
        catch(Exception Ex)
        {
              sw.WriteLine(Ex.ToString());
              sw.Flush();
        }
    }

    void timerNew_Elapsed(object sender, ElapsedEventArgs e)
    {
      sw.WriteLine("timer is working...{0}", DateTime.Now.ToString());

      SqlConnection conn;
      SqlCommand comm;

      conn = new SqlConnection(@"Data Source=.;Initial Catalog=MailDB;Integrated Security=True");
      comm = new SqlCommand("select Text,product from Source", conn);

      conn.open();
      SqlDataReader rd = comm.ExecuteReader();
      while (rd.Read())
      {
        if (Convert.ToInt32(rd["Text"]) < 20)
        {
          sw.WriteLine("{0}  stock state {1}", rd["product"].ToString(), rd["stock"].ToString());
        }
      }

      sw.Flush();
    }

    protected override void OnStop()
    {
    }
  }

I want to use Windows service for my project. When I use those codes I don't have any problems.

Problem is when I add some SQL code in timer blocks. I have some effect in SampleLast.text file. Just running codes where OnStart() methods. I can't understand what is problem.Problem is when i use sqllconnection and sqlcommand codes, timer dosent work.

---

conn = new SqlConnection(@"Data Source=.;Initial Catalog=MailDB;Integrated Security=True");
comm = new SqlCommand("select Text,product from Source", conn);
SqlDataReader rd = comm.ExecuteReader();

You don't mention what your problem is, but you are never actually opening your SQL connection, so this should never have worked.

I'd recommend refactoring and using using blocks:

using(SqlConnection conn = new SqlConnection(@"Data Source=.;Initial Catalog=MailDB;Integrated Security=True"))
using (SqlCommand comm = new SqlCommand("select Text,product from Source", conn))
{
    conn.Open();
    using (SqlDataReader rd = comm.ExecuteReader())
    {
        //...
    }
}