C#/MySQL-only outputs one query to a file

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Mono

C#

.NET

MySQL

Hello,

I have a MySQL query in C# and I'm trying to write the results of the entire query to a file. However, the code will only write the first query result into the text file. When I tell it to output to the console though it displays all 500 results. I know that my problem may have something to do with newline in the string called result. I've been Googling for a long time on how to fix this- need the help. Thanks.

The output to the text file should look like:
x1,x2,x3,x4
x1,x2,x3,x4
...

Right now I am only getting:
x1,x2,x3,x4

The code is here:

using System;
using System.Data;
using System.IO;
using MySql.Data.MySqlClient;
using System.Text;
using System.Collections.Generic;
using System.Diagnostics;

namespace sqljunk1
{
	class MainClass
	{
		public static void Main (string[] args)
		{
			string result="";
			string connectionString =
          			"Server=localhost;" +
          			"Database=mysql;" +
          			"User ID=***;" +
          			"Password=***;" +
          			"Pooling=false";
       			
		IDbConnection dbcon;
       		dbcon = new MySqlConnection(connectionString);
       		dbcon.Open();
       		IDbCommand dbcmd = dbcon.CreateCommand();
      
			string sql =
           		"SELECT x1, x2, x3, x4" +"FROM table " 
			+"WHERE x3 like '%GJ71%'";
       		
		dbcmd.CommandText = sql;
       		IDataReader reader = dbcmd.ExecuteReader();
       	
	while(reader.Read()) 
		{
            string x1 = (string) reader["x1"];
            string x2 = (string) reader["x2"];
	    string x3 = (string) reader["x3"];
            string x4 = (string) reader["x4"];
			
	    result= x1+","+x2+","+x3+","+x4+; 	
 		
				
System.IO.StreamWriter file= new System.IO.StreamWriter("example.txt");
	    file.WriteLine(result);
	    file.Close();
			
		}
			
       reader.Close();
       reader = null;
       dbcmd.Dispose();
       dbcmd = null;
       dbcon.Close();
       dbcon = null;

		}
	}
}