cannot convert from 'string' to 'System.Collections.Generic.IEnumerabl

Question

Im trying to export results to a txt file, I need to include all rows and columns. In my query below I can see in the console all the rows and columns, when I use "File.WriteAllText", it only write one row with all columns, when I try to use "File.WriteAllLines" i receive the error msg "cannot convert from 'string' to 'System.Collections.Generic.IEnumerable" . any help really appreciated

using System;
using Microsoft.AnalysisServices.AdomdClient;
using System.IO;
using System.Diagnostics;
using System.Text;
using System.Collections.Generic;
using System.Linq;
namespace DaxQuery
{
class Program
{
private const string V = "";
static void Main(string[] args)
{
AdomdConnection adomdConnection = new AdomdConnection("Data Source=localhost:60100");
String query = @"
EVALUATE
SUMMARIZECOLUMNS(
Customer[City],
Customer[Country-Region],
Customer[Customer],
Customer[Customer ID]
)
";
AdomdCommand adomdCommand = new AdomdCommand(query,adomdConnection);
/*******************************************************
connection
*******************************************************/
adomdConnection.Open();
AdomdDataReader reader = adomdCommand.ExecuteReader();
// Create a loop for every row in the resultset
while(reader.Read())
{
String rowResults = "";
// Create a loop for every column in the current row --need to add header
for (
int columnNumber = 0;
columnNumber<reader.FieldCount;
columnNumber++
)
{
rowResults += $"\t{reader.GetValue(columnNumber)}";
}
//Console.WriteLine(rowResults);
File.WriteAllText(@"C:\Temp\output.txt", rowResults) ;
//File.WriteAllLines(@"C:\Temp\output.txt", rowResults) ;
//
//string rowResults1 = (rowResults);
//var query1 = rowResults1;
//File.WriteAllLines(@"C:\Temp\output.txt", query1);
//
}
adomdConnection.Close();
}
}
}