Creating a CSV File in C#

Question

I am trying to created a csv file where each entry is inputed by the user. Once one set of of values have been entered it should move on to the next. However I cannot seem to do the bit. Each time i run the program, it replaces the previous values.

using System;
using System.IO;
using System.Collections.Generic;


namespace FileAccess
{
    class MainClass
    {
        public static void Main(string[] args)
        {
            string FName;
            string LName;
            string Dpt;
            string Grade;
            string NumberOfHours;

            string file_name = "EmployeeDetails.txt";

            System.IO.StreamWriter objWriter;
            objWriter = new System.IO.StreamWriter(file_name);

            String[] ArrayDetails = new string[5];

            Console.Write("Enter Emp First Name: ");
            FName=Console.ReadLine();
            Console.Write("Enter Emp Last Name: ");
            LName = Console.ReadLine();
            Console.Write("Enter Emp Department: ");
            Dpt = Console.ReadLine();
            Console.Write("Enter Employee Grade: ");
            Grade = Console.ReadLine();
            Console.Write("Enter Number Of Hours Worked: ");
            NumberOfHours = Console.ReadLine();

            ArrayDetails[0] = FName;
            ArrayDetails[1] = LName;
            ArrayDetails[2] = Dpt;
            ArrayDetails[3] = Grade;
            ArrayDetails[4] = NumberOfHours;

            // Create new list of strings
            List<string> LDetails = new List<string>(); // Create new list of strings
            LDetails.Add(FName); // Add string 1
            LDetails.Add(LName); // 2
            LDetails.Add(Dpt); // 3
            LDetails.Add(Grade); // 4
            LDetails.Add(NumberOfHours); // 5
            //OutPut the data into the file
            string LDetailsCSV = string.Join(",", LDetails.ToArray());
            Console.WriteLine(LDetailsCSV);
            objWriter.Write(LDetailsCSV);
            objWriter.Close();
        }
    }
}

Some advise please.

Answer 1

The StreamWriter constructor will overwrite the file you are using if it exists. There is an overloaded constructor to which you can pass a boolean as a second argument to tell it to append:

System.IO.StreamWriter objWriter;
objWriter = new System.IO.StreamWriter(file_name, true);

In addition, the Write method you are using will not append a line break. If you use the WriteLine method, it will.

 Console.WriteLine(LDetailsCSV);
 objWriter.WriteLine(LDetailsCSV);
 objWriter.Close();

Answer 2

You have to open the file in append mode, like this:

System.IO.StreamWriter objWriter;
objWriter = new File.AppendText(file_name);