在C#中的txt文件中写入矩阵

using System;
using System.IO;

class Program
{
    static void Main(string[] args)
    {
        int[,] matrix = new int[,] {
            { 1, 2, 3 },
            { 4, 5, 6 },
            { 7, 8, 9 }
        };

        WriteMatrixToFile(matrix, "matrix.txt");
    }

    static void WriteMatrixToFile(int[,] matrix, string fileName)
    {
        using (FileStream fs = new FileStream(fileName, FileMode.Create))
        {
            using (StreamWriter sw = new StreamWriter(fs))
            {
                for (int i = 0; i< matrix.GetLength(0); i++)
                {
                    for (int j = 0; j< matrix.GetLength(1); j++)
                    {
                        sw.Write(matrix[i, j]);

                        if (j< matrix.GetLength(1) - 1)
                        {
                            sw.Write(",");
                        }
                    }

                    sw.WriteLine();
                }
            }
        }
    }
}