C# 获取文件夹里所有文件名

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.IO;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using Renci.SshNet;
namespace GetFileNames
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();

            textBox1.Text = @"";//文件路径
            textBox2.Text = "";//格式
        }

        string _outFileName = "";

        private void button1_Click(object sender, EventArgs e)
        {

            DirectoryInfo folder = new DirectoryInfo(textBox1.Text);

            foreach (FileInfo file in folder.GetFiles(textBox2.Text))
            {
                richTextBox1.AppendText("node "+file.Name+'\n');
            }

            OutputFile(textBox1.Text + @"\"+ _outFileName, richTextBox1.Text);
        }

        void OutputFile(string strFilePath,string strContent)
        {
            StreamWriter swOut = new StreamWriter(strFilePath, false, Encoding.Default);
            swOut.WriteLine(strContent);
            swOut.Flush();
            swOut.Close();
        }

    }
}