winform实现FTP上传、下载、删除文件（附源码下载）

一个用winform开发的FTP上传、下载、删除文件的简单列子:

配套源码下载：https://download.csdn.net/download/djk8888/10473477

注释尽可能详尽，希望大家一看就会。

页面相关代码：

using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Text.RegularExpressions;
using System.Windows.Forms;

namespace winform_ftp
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.cmbFolder.Text = "默认文档";
            Bind();
        }
        //刷新
        private void btnRefresh_Click(object sender, EventArgs e)
        {
            Bind();
        }
        private void Bind()
        {
            FileStream fs = new FileStream(Application.StartupPath + "\\db.txt", FileMode.Open);
            StreamReader sr = new StreamReader(fs, Encoding.Default);
            var jsonStr = sr.ReadToEnd();//取出json字符串
            sr.Close();
            fs.Close();

            List<FtpEntity> temp = new List<FtpEntity>();
            var dt = JsonHelper.JsonToObject(jsonStr.Trim(), temp);
            if (dt != null)
            {
                this.dataGridView1.DataSource = dt;
                dataGridView1.Columns["ID"].Width = 50;
                dataGridView1.Columns["FileName"].Width = 150;
                dataGridView1.Columns["FileFullName"].Width = 300;
                dataGridView1.Columns["FileUrl"].Width = 150;
            }
        }
        //下载
        private void btnDownload_Click(object sender, EventArgs e)
        {
            if (dataGridView1.Rows[LastSelectRowIndex].Cells[0].Value != null)
            {
                if ((bool)dataGridView1.Rows[LastSelectRowIndex].Cells[0].Value == true)
                {
                    string FileFullName = dataGridView1.Rows[LastSelectRowIndex].Cells["FileFullName"].Value.ToString().Trim();
                    string FileUrl = dataGridView1.Rows[LastSelectRowIndex].Cells["FileUrl"].Value.ToString().Trim();

                    FolderBrowserDialog fbd = new FolderBrowserDialog();//文件选择框
                    DialogResult dr = fbd.ShowDialog();//选择下载的路径
                    if (dr == DialogResult.Cancel) return;
                    string LocalDir = fbd.SelectedPath + "\\" + FileFullName;//本地保存文件路径+文件名
                    fbd.Dispose();

                    Application.DoEvents();
                    try
                    {
                        var b = FtpHelper.Down(FileUrl, FileFullName, LocalDir);
                        if (b == true)
                        {
                            MessageBox.Show("文件：" + FileFullName + "下载成功!");
                            foreach (DataGridViewRow dgvr in dataGridView1.Rows)
                            {
                                dgvr.Cells["check"].Value = false;
                            }
                        }
                        else
                        {
                            MessageBox.Show("文件下载失败!");
                        }
                    }
                    catch (Exception ex)
                    {
                        MessageBox.Show(ex.ToString());
                    }
                }
            }
        }
        //上传
        private void btnUpload_Click(object sender, EventArgs e)
        {
            //文件选择器
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.Filter = "支持的文件格式(word,excel,pdf,文本,图片)|*.doc;*.docx;*.xls;*.xlsx;*.pdf;*.txt;*.jpg;*.jpeg;|Word文件(*.doc;*.docx)|*.doc;*.docx|Excel文件(*.xls;*.xlsx)|*.xls;*.xlsx|文本文件(*.txt)|*.txt|图片文件(*.jpg;*.jpeg)|*.jpg;*.jpeg";
            if (ofd.ShowDialog() == System.Windows.Forms.DialogResult.Cancel) return;

            string ofdLocalFileName = ofd.FileName;//文件本地路径
            ofd.Dispose();

            //判断是否选择文件
            FileInfo fi = new FileInfo(ofdLocalFileName);
            if (!fi.Exists)
            {
                MessageBox.Show("请选择一个文件");
                return;
            }
            //判断文件格式
            if (!".doc.docx.xls.xlsx.pdf.txt.jpg.jpeg".Contains(fi.Extension.ToLower()))
            {
                MessageBox.Show("不支持的文件格式");
                return;
            }
            //判断文件大小
            if (fi.Length > 1024 * 1024 * 1)//文件限制：1mb
            {
                MessageBox.Show("文件内容过大！请上传小于1mb的文件！");
                return;
            }
            //准备上传
            fi = new FileInfo(ofdLocalFileName);
            string FileName = Regex.Replace(fi.Name.Replace(fi.Extension, ""), "\\s+", "");
            FileName = FileName.Replace("#", "$");//文件名称(不含扩展名)(存数据库用于查询，如：文件名相同的，但类型不同的文件：文件1.txt、文件1.doc、文件1.jpg、文件1.pdf)
            string FileType = fi.Extension.ToLower().Trim();//文件扩展名(存数据库，用于分类)
            string FileFullName = FileName + "_" + DateTime.Now.ToString("yyyyMMddHHmmssfff") + fi.Extension.Trim();//文件完整名称(含扩展名，用于下载，重要！必须！)
            DateTime UploadTime = DateTime.Now;//上传时间(存数据库，用于查询)
            string FileDir = cmbFolder.Text + "/" + UploadTime.ToString("yyyyMMdd");//路径(文件夹+日期，重要！必须！)

            try
            {
                FtpHelper.CreateDirectory(cmbFolder.Text);//创建根文件夹(可自定义)
            }
            catch { }   //如果文件夹已存在，就跳过!
            try
            {
                FtpHelper.CreateDirectory(FileDir);//创建子文件夹(年月日期)
            }
            catch { }   //如果文件夹已存在，就跳过!

            FtpHelper.FileDir = FileDir;//上传路径

            var result = FtpHelper.Upload(FileFullName, ofdLocalFileName);//开始FTP上传文件!
            if (result == true)//上传成功后，写入数据库(sqlServer,mySql等等...)
            {
                try
                {
                    //此处，txt文件“db.txt”充当数据库文件，用于存放、读写、删除,json数据对象集合(即json字符串)
                    FileStream fs = new FileStream(Application.StartupPath + "\\db.txt", FileMode.Open);
                    StreamReader sr = new StreamReader(fs, Encoding.Default);
                    var jsonStr = sr.ReadToEnd();
                    List<FtpEntity> temp = new List<FtpEntity>();
                    var dt = JsonHelper.JsonToObject(jsonStr.Trim(), temp);
                    sr.Close();
                    fs.Close();

                    if (dt != null)
                    {
                        List<FtpEntity> list = (List<FtpEntity>)dt;//object转List<T>
                        FtpEntity entity = new FtpEntity();
                        if (list != null && list.Count > 0)
                        {
                            entity.ID = list[list.Count - 1].ID + 1;//新ID=原最大ID值+1
                        }
                        else
                        {
                            entity.ID = 1;
                        }
                        entity.FileFullName = FileFullName;
                        entity.FileName = FileName;
                        entity.FileType = FileType;
                        entity.FileUrl = FileDir;
                        entity.UploadTime = UploadTime;

                        list.Add(entity);//数据集合添加一条新数据

                        string json = JsonHelper.ObjectToJson(list);//list集合转json字符串

                        StreamWriter sw = new StreamWriter(Application.StartupPath + "\\db.txt", false, System.Text.Encoding.UTF8);//参数2：false覆盖;true追加
                        sw.WriteLine(json);//写入文件
                        sw.Close();
                        MessageBox.Show("上传成功!");
                        Bind();//刷新列表
                    }
                }
                catch (Exception ex)
                {
                    MessageBox.Show("文件上传成功!但写入数据库失败：\r\n" + ex.ToString());//请检查文件夹的读写权限
                }
            }
            else
            {
                MessageBox.Show("上传失败!");
            }
        }
        //列表单选
        int LastSelectRowIndex = default(int);
        private void dataGridView1_CellContentClick(object sender, DataGridViewCellEventArgs e)
        {
            try
            {
                if (e.RowIndex >= 0)
                {
                    //选择的是checkBox
                    if (dataGridView1.Columns[e.ColumnIndex] is DataGridViewCheckBoxColumn)
                    {
                        if (LastSelectRowIndex == e.RowIndex)
                        {
                            return;
                        }
                        else
                        {
                            if (dataGridView1.Rows[LastSelectRowIndex].Cells[0].Value != null)
                            {
                                if ((bool)dataGridView1.Rows[LastSelectRowIndex].Cells[0].Value)
                                {
                                    dataGridView1.Rows[LastSelectRowIndex].Cells[0].Value = false;
                                }
                            }
                        }
                        LastSelectRowIndex = e.RowIndex;
                    }
                }
            }
            catch
            {
                foreach (DataGridViewRow dgvr in dataGridView1.Rows)
                {
                    dgvr.Cells["check"].Value = false;
                }
            }
        }

        private void btnDelete_Click(object sender, EventArgs e)
        {
            if (MessageBox.Show("确认删除？", "提示", MessageBoxButtons.YesNo, MessageBoxIcon.Question) == DialogResult.Yes)
            {
                if (dataGridView1.Rows[LastSelectRowIndex].Cells[0].Value != null)
                {
                    if ((bool)dataGridView1.Rows[LastSelectRowIndex].Cells[0].Value == true)
                    {
                        string FileFullName = dataGridView1.Rows[LastSelectRowIndex].Cells["FileFullName"].Value.ToString().Trim();
                        string FileUrl = dataGridView1.Rows[LastSelectRowIndex].Cells["FileUrl"].Value.ToString().Trim();
                        string ID = dataGridView1.Rows[LastSelectRowIndex].Cells["ID"].Value.ToString().Trim();

                        var b = FtpHelper.Delete(FileUrl, FileFullName);
                        if (b)
                        {
                            FileStream fs = new FileStream(Application.StartupPath + "\\db.txt", FileMode.Open);
                            StreamReader sr = new StreamReader(fs, Encoding.Default);
                            var jsonStr = sr.ReadToEnd();
                            List<FtpEntity> Entity = new List<FtpEntity>();
                            var dt = JsonHelper.JsonToObject(jsonStr.Trim(), Entity);
                            sr.Close();
                            fs.Close();

                            List<FtpEntity> list = (List<FtpEntity>)dt;//object转List<T>
                            FtpEntity delEntity = list.Find(a => a.ID == int.Parse(ID));//根据ID值取出对象
                            list.Remove(delEntity);//从列表中删除此对象

                            string json = JsonHelper.ObjectToJson(list);//将新的list转成json写入txt

                            StreamWriter sw = new StreamWriter(Application.StartupPath + "\\db.txt", false, System.Text.Encoding.UTF8);//参数2：false覆盖;true追加
                            sw.WriteLine(json);//写入文件
                            sw.Close();

                            MessageBox.Show("删除FTP上的文件成功!");
                            Bind();
                        }
                        else
                        {
                            MessageBox.Show("删除FTP上的文件失败!");
                        }
                    }
                }
            }
        }
    }
}

FTP相关代码：

using System;
using System.IO;
using System.Net;

namespace winform_ftp
{
    /// <summary>
    /// 请勿上传违法、违规等不和谐的文件!
    /// CSDN博客:https://blog.csdn.net/djk8888
    /// 腾讯微博:http://t.qq.com/djk8888
    /// </summary>
    public class FtpHelper
    {
        public static string FileDir { get; set; }
        public static string FtpHost = "ftp://013.3vftp.com/";//ftp地址(如果ftp测试空间满了，请登上ftp删掉点测试文件即可)
        public static string FtpUser = "djk8888csdn";//ftp账号(请勿上传违法、违规等不和谐的文件!)
        public static string FtpPassword = "123456";//ftp密码(别怀疑，就是：123456)
        //请勿上传违法、违规等不和谐的文件!重要的事说三遍！本人概不负责!

        /// <summary>
        /// FTP下载文件
        /// </summary>
        /// <param name="RemoteDir">FTP上的文件路径</param>
        /// <param name="RemoteFileName">完整文件名</param>
        /// <param name="LocalDir">下载到本地的路径</param>
        public static bool Down(string RemoteDir, string RemoteFileName, string LocalDir)
        {
            try
            {
                FileStream outputStream = new FileStream(LocalDir, FileMode.Create, FileAccess.Write);//新建本地文件(空文件)
                outputStream.Close();//关闭IO
                return Download(RemoteDir, RemoteFileName, LocalDir);//将FTP上的文件内容写入到本地空文件中去
            }
            catch
            {
                return false;//新建本地文件失败
            }
        }
        private static bool Download(string RemoteDir, string RemoteFileName, string LocalDir)
        {
            FtpWebRequest reqFTP;
            try
            {
                //①读取FTP上的文件
                FileStream outputStream = new FileStream(LocalDir, FileMode.Create);//建立FTP链接
                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(FtpHost + RemoteDir + "/" + RemoteFileName));//读取FTP上的文件
                reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;//FTP下载协议
                reqFTP.UseBinary = true;//指定文件传输类型
                reqFTP.Credentials = new NetworkCredential(FtpUser, FtpPassword);//FTP通信凭证(即登录ftp)
                FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();//登录成功
                //②将FTP上的文件内容转化成数据流
                Stream ftpStream = response.GetResponseStream();//将FTP上的文件转化为数据流              
                int bufferSize = 2048;//缓冲大小，单位byte               
                byte[] buffer = new byte[bufferSize];//数据包
                int readCount;//循环次数
                readCount = ftpStream.Read(buffer, 0, bufferSize);//计算循环次数
                //③将FTP文件内容写入到本地空文件中去
                while (readCount > 0)
                {
                    outputStream.Write(buffer, 0, readCount);//写入每一次读取的数据流
                    readCount = ftpStream.Read(buffer, 0, bufferSize);//重新计算次数
                }
                //④关闭IO
                ftpStream.Close();
                outputStream.Close();
                response.Close();
                return true;
            }
            catch //(Exception ex)
            {
                return false;
            }
        }

        /// <summary>
        /// 创建文件夹
        /// </summary>
        /// <param name="RemoteDir">FTP上文件路径</param>
        /// <returns></returns>
        public static string CreateDirectory(string RemoteDir)
        {
            FtpWebRequest request = SetFtpConfig(WebRequestMethods.Ftp.MakeDirectory, RemoteDir);
            FtpWebResponse response = (FtpWebResponse)request.GetResponse();
            return response.StatusDescription;
        }
        private static FtpWebRequest SetFtpConfig(string method, string RemoteDir)
        {
            return SetFtpConfig(method, RemoteDir, "");
        }
        private static FtpWebRequest SetFtpConfig(string method, string RemoteDir, string RemoteFileName)
        {
            RemoteDir = string.IsNullOrEmpty(RemoteDir) ? "" : RemoteDir.Trim();
            return SetFtpConfig(FtpHost, FtpUser, FtpPassword, method, RemoteDir, RemoteFileName);
        }
        private static FtpWebRequest SetFtpConfig(string host, string username, string password, string method, string RemoteDir, string RemoteFileName)
        {
            System.Net.ServicePointManager.DefaultConnectionLimit = 50;
            FtpWebRequest request = (FtpWebRequest)WebRequest.Create(host + RemoteDir + "/" + RemoteFileName);
            request.Method = method;
            request.Credentials = new NetworkCredential(username, password);
            request.UsePassive = false;
            request.UseBinary = true;
            request.KeepAlive = false;
            return request;
        }
        /// <summary>
        /// FTP上传文件
        /// </summary>
        /// <param name="FileName">上传到FTP后的文件名</param>
        /// <param name="localFileName">本地选择的文件名</param>
        /// <param name="falsegz"></param>
        /// <returns></returns>
        public static bool Upload(string FileName, string localFileName)
        {
            return Upload(FileDir, FileName, localFileName);
        }
        private static bool Upload(string FileDir, string FileName, string localFileName)
        {
            try
            {
                //①在FTP上创建一个空文件:
                FtpWebRequest request = SetFtpConfig(WebRequestMethods.Ftp.UploadFile, FileDir, FileName);//创建空文件
                //②读取本地文件的内容，转化成流：
                FileStream fs = new FileStream(localFileName, FileMode.Open, FileAccess.Read);//打开本地文件
                int buffLength = 20480;//缓存大小，单位byte
                byte[] buff = new byte[buffLength];//数据包
                var contentLen = fs.Read(buff, 0, buffLength);//每次读文件流的kb     
                //③将本地文件的内容，写入到FTP上空文件中去：
                Stream strm = request.GetRequestStream(); //把上传的文件写入本地文件的流                             
                while (contentLen != 0)//流内容没有结束，循环  
                {
                    strm.Write(buff, 0, contentLen);// 把内容从file stream 写入upload stream  
                    contentLen = fs.Read(buff, 0, buffLength);//读取流
                }
                //④关闭IO
                strm.Close();
                fs.Close();
                return true;//返回成功
            }
            catch //(Exception ex)
            {
                return false;
            }
        }
        /// <summary>  
        /// 删除文件  
        /// </summary>  
        /// <param name="FileDir">ftp文件路径(不包含文件名)</param>  
        /// <param name="FileName">文件名</param>  
        /// <returns>返回值</returns>  
        public static bool Delete(string FileDir, string FileName)
        {
            bool success = false;
            FtpWebRequest ftpWebRequest = null;
            FtpWebResponse ftpWebResponse = null;
            Stream ftpResponseStream = null;
            StreamReader streamReader = null;
            try
            {
                string uri = FtpHost + FileDir + "/" + FileName;//例：ftp://013.3vftp.com/默认文档/20180608/文件1.txt
                ftpWebRequest = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri));
                ftpWebRequest.Credentials = new NetworkCredential(FtpUser, FtpPassword);
                ftpWebRequest.KeepAlive = false;
                ftpWebRequest.Method = WebRequestMethods.Ftp.DeleteFile;
                ftpWebResponse = (FtpWebResponse)ftpWebRequest.GetResponse();
                long size = ftpWebResponse.ContentLength;
                ftpResponseStream = ftpWebResponse.GetResponseStream();
                streamReader = new StreamReader(ftpResponseStream);
                string result = String.Empty;
                result = streamReader.ReadToEnd();
                success = true;
            }
            catch (Exception)
            {
                success = false;
            }
            finally
            {
                if (streamReader != null)
                {
                    streamReader.Close();
                }
                if (ftpResponseStream != null)
                {
                    ftpResponseStream.Close();
                }
                if (ftpWebResponse != null)
                {
                    ftpWebResponse.Close();
                }
            }
            return success;
        }
    }
}

配套源码下载：https://download.csdn.net/download/djk8888/10473477

webForm的ftp上传下载：https://blog.csdn.net/djk8888/article/details/80736524