Dumping SQL table to .csv C#

I am trying to implement a script in my application that will dump the entire contents (for now, but I am trying to write the code so that I can easily customize it to only grab certain columns) of a sql db (running ms sql server express 2014) to a .csv file.

Here is the code I have written currently:

        public void doCsvWrite(string timeStamp){       
        try {
            //specify file name of log file (csv).
            string newFileName = "C:/TestDirectory/DataExport-" + timeStamp + ".csv";
            //check to see if file exists, if not create an empty file with the specified file name.
            if (!File.Exists(newFileName)) {
                FileStream fs = new FileStream(newFileName, FileMode.CreateNew);
                fs.Close();
                //define header of new file, and write header to file.
                string csvHeader = "ITEM1,ITEM2,ITEM3,ITEM4,ITEM5";
                using (FileStream fsWHT = new FileStream(newFileName, FileMode.Append, FileAccess.Write))
                using(StreamWriter swT = new StreamWriter(fsWHT))
                {
                    swT.WriteLine(csvHeader.ToString());
                }
            }
            //set up connection to database.
            SqlConnection myDEConnection;   
            String cDEString = "Data Source=localhost\NAMEDPIPE;Initial Catalog=db;User Id=user;Password=pwd";
            String strDEStatement = "SELECT * FROM table"; 

            try
            {
                myDEConnection = new SqlConnection(cDEString);
            }
            catch (Exception ex)
            {  
                //error handling here.
                return;
            }

            try
            {
                myDEConnection.Open();
            }
            catch (Exception ex)
            {
                //error handling here.
                return;
            }
            SqlDataReader reader = null;
            SqlCommand myDECommand = new SqlCommand(strDEStatement, myDEConnection);
            try
            {
                reader = myDECommand.ExecuteReader();
                while (reader.Read())
                {
                    for (int i = 0; i < reader.FieldCount; i++)
                    {
                        if(reader["Column1"].ToString() == "") {
                            //does nothing if the current line is "bugged" (containing no values at all, typically happens after reboot of 3rd party equipment).
                        }
                        else {
                            //grab relevant tag data and set the csv line for the current row.
                            string csvDetails = reader["Column1"] + "," + reader["Column2"] + "," + String.Format("{0:0.0}", reader["Column3"]) + "," + String.Format("{0:0.000}", reader["Column4"]) + "," + reader["Column5"];

                            using (FileStream fsWDT = new FileStream(newFileName, FileMode.Append, FileAccess.Write))
                            using(StreamWriter swDT = new StreamWriter(fsWDT))
                            {
                                //write csv line to file.
                                swDT.WriteLine(csvDetails.ToString());
                            }
                        }
                    }
                }
            }
            catch (Exception ex)
            {
                //error handling here.
                myDEConnection.Close();
                return;
            }
            myDEConnection.Close();
        }
        catch (Exception ex)
        {
            //error handling here.
            MessageBox.Show(ex.Message);
        }
    }

Now, this was working fine when I was using it with a 3rd party SQLite-based database, but the output I’m getting after modifing this to my MSSQL db looks something like this (ITEM1 is the primary key, a standard auto-incrementing ID-field):

ITEM1,ITEM2,ITEM3,ITEM4,ITEM5
1,row1_item2,row1_item3,row1_item4,row1_item5
1,row1_item2,row1_item3,row1_item4,row1_item5
1,row1_item2,row1_item3,row1_item4,row1_item5
1,row1_item2,row1_item3,row1_item4,row1_item5
1,row1_item2,row1_item3,row1_item4,row1_item5
1,row1_item2,row1_item3,row1_item4,row1_item5
2,row2_item2,row2_item3,row2_item4,row2_item5
2,row2_item2,row2_item3,row2_item4,row2_item5
2,row2_item2,row2_item3,row2_item4,row2_item5
2,row2_item2,row2_item3,row2_item4,row2_item5
2,row2_item2,row2_item3,row2_item4,row2_item5
3,row3_item2,row3_item3,row3_item4,row3_item5
3,row3_item2,row3_item3,row3_item4,row3_item5
3,row3_item2,row3_item3,row3_item4,row3_item5
3,row3_item2,row3_item3,row3_item4,row3_item5
....

So it seems that it writes several entries of the same row, where I would just like one single line each row. Any suggestions?

Thanks in advance.

edit: Thanks everyone for your answers!

Answer

The for loop isn’t needed in the section below. Because it loops from 0 to FieldCount I assume the loop was originally meant to append the text from each column together but inside the loop there’s a single line that concatenates the text and assigns it to csvDetails.

        try
        {
            reader = myDECommand.ExecuteReader();
            while (reader.Read())
            {
                for (int i = 0; i < reader.FieldCount; i++)
                {
                    if(reader["Column1"].ToString() == "") {
                        //does nothing if the current line is "bugged" (containing no values at all, typically happens after reboot of 3rd party equipment).
                    }
                    else {
                        //grab relevant tag data and set the csv line for the current row.
                        string csvDetails = reader["Column1"] + "," + reader["Column2"] + "," + String.Format("{0:0.0}", reader["Column3"]) + "," + String.Format("{0:0.000}", reader["Column4"]) + "," + reader["Column5"];

                        using (FileStream fsWDT = new FileStream(newFileName, FileMode.Append, FileAccess.Write))
                        using(StreamWriter swDT = new StreamWriter(fsWDT))
                        {
                            //write csv line to file.
                            swDT.WriteLine(csvDetails.ToString());
                        }
                    }
                }
            }
        }