Question

 SqlConnection connection = new SqlConnection(@"Data Source=localhost\SQLEXPRESS;Initial Catalog=PSeminar;Integrated Security=true;Trusted_Connection=Yes;MultipleActiveResultSets=true");
        SqlCommand Command = connection.CreateCommand();

        SqlDataReader SQLRD;

        Command.CommandText = "Select * from Attendance";

        connection.Open();
        SQLRD = Command.ExecuteReader();


        string data = "";



        while (SQLRD.Read())
        {
            data += SQLRD[0].ToString() + ",";
            data += SQLRD[1].ToString() + ",";
            data += SQLRD[2].ToString() + ",";
            data += SQLRD[3].ToString() + ",";
            data += SQLRD[4].ToString() + ",";
            data += SQLRD[5].ToString() + ",";
            data += SQLRD[6].ToString() + ",";
            data += SQLRD[7].ToString();
            data += "\n";

        }

        SQLRD.Close();
        connection.Close();

        string filename = @"C:\download.csv";
        FileStream fs = new FileStream(filename,FileMode.Append, FileAccess.Write);
        StreamWriter sw = new StreamWriter(fs);
        sw.WriteLine(data);
        sw.Flush();
        sw.Close();
        fs.Close();

Currently my code does not display a dialog box for the user to specify the file location. It is “hardcoded” to always store in @”C:\download.csv”;. In replace of this i want to use a dialog box.

Answer 1

First of all I’d say do not use System.String object to contact strings. Always use System.Text.StringBuilder object.

System.Text.StringBuilder sb = new System.Text.StringBuilder();
 while (SQLRD.Read())
  {
  sb.Append(String.Format("{0},{1},{2},{3},{4},{5},{6},{7}\n",
      SQLRD[0],SQLRD[1],SQLRD[2],SQLRD[3],SQLRD[4],SQLRD[5],SQLRD[6],SQLRD[7]));
   }

To download data,

byte[] ar = System.Text.Encoding.UTF8.GetBytes(sb.ToString());
Response.ClearContent();
Response.ClearHeaders();
Response.AddHeader("Content-Type", "application/octet-stream");
Response.AddHeader("Content-Length", ar.Length.ToString());
Response.AddHeader("Content-Disposition", "attachment; filename=download.csv");
Response.BinaryWrite(ar);
Response.Flush();
Response.End();