OpenFileDialog opFilDlg = new OpenFileDialog();
if (opFilDlg.ShowDialog() == DialogResult.OK)
{   ftp = new YBBFTPClass("hz.a.cn", "", "csp", "welcome", 0);
    ftp.UploadFile(opFilDlg.FileName);
    MessageBox.Show("上傳成功");
}

/// <summary>
/// 文件上傳
/// </summary>
/// <param name="filename">本地文件路徑</param>
public void UploadFile(string filename)
{
    FileInfo fileInf = new FileInfo(filename);
    string uri = "ftp://" + RemoteHost + "/" + fileInf.Name;
    FtpWebRequest reqFTP;

    reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + RemoteHost + "/" + fileInf.Name));// 根據(jù)uri創(chuàng)建FtpWebRequest對象
    reqFTP.Credentials = new NetworkCredential(RemoteUser, RemotePass);    // ftp用戶名和密碼
    reqFTP.KeepAlive = false;    // 默認(rèn)為true，連接不會被關(guān)閉， 在一個命令之后被執(zhí)行
    reqFTP.Method = WebRequestMethods.Ftp.UploadFile;    // 指定執(zhí)行什么命令
    reqFTP.UseBinary = true;   // 指定數(shù)據(jù)傳輸類型
    reqFTP.ContentLength = fileInf.Length;    // 上傳文件時通知服務(wù)器文件的大小

    int contentLen;
    FileStream fileStream = fileInf.OpenRead(); // 打開一個文件讀取內(nèi)容到fileStream中
    contentLen = fileStream.Read(buffer, 0, buffer.Length); ;//從fileStream讀取數(shù)據(jù)到buffer中

    Stream requestStream = reqFTP.GetRequestStream();
    // 流內(nèi)容沒有結(jié)束
    while (contentLen != 0)
    {
        requestStream.Write(buffer, 0, contentLen);// 把內(nèi)容從buffer 寫入 requestStream中，完成上傳。
        contentLen = fileStream.Read(buffer, 0, buffer.Length);
    }

    // 關(guān)閉兩個流
    requestStream.Close();
    //uploadResponse = (FtpWebResponse)reqFTP.GetResponse();
    fileStream.Close();
}

/// <summary>
/// 下載文件
/// </summary>
/// <param name="filePath">本地目錄</param>
/// <param name="fileName">遠(yuǎn)程路徑</param>
public void DownloadFile(string filePath, string fileName)
{
    FtpWebRequest reqFTP;
    try
    {
        FileStream fileStream = new FileStream(filePath + "\\" + fileName, FileMode.Create);

        reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + RemoteHost + "/" + fileName));
        reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;
        reqFTP.UseBinary = true;
        reqFTP.Credentials = new NetworkCredential(RemoteUser, RemotePass);

        FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
        Stream responseStream = response.GetResponseStream();//從ftp響應(yīng)中獲得響應(yīng)流

        //long cl = response.ContentLength;
        byte[] buffer = new byte[1024];
        int readCount;

        readCount = responseStream.Read(buffer, 0, buffer.Length);//從ftp的responseStream讀取數(shù)據(jù)到buffer中
        while (readCount > 0)
        {
            fileStream.Write(buffer, 0, readCount);//從buffer讀取數(shù)據(jù)到fileStream中，完成下載
            readCount = responseStream.Read(buffer, 0, buffer.Length);
        }

        responseStream.Close();
        fileStream.Close();
        response.Close();
    }
    catch (Exception ex)
    {
        Console.WriteLine(ex.Message);
    }
}

FolderBrowserDialog fldDlg = new FolderBrowserDialog();
if (txtUpload.Text.Trim().Length > 0)
{
    if (fldDlg.ShowDialog() == DialogResult.OK)
    {
        ftp.DownloadFile(fldDlg.SelectedPath, txtUpload.Text.Trim());
        MessageBox.Show("下載成功");
    }
}
else
{
    MessageBox.Show("Please enter the File name to download");
}

FtpClient _client = new FtpClient();
Stream stream = _client.OpenRead(FtpFilePath, FtpDataType.Binary);

string FtpFilePath = Request.QueryString["FilePath"];
string _fname = Path.GetFileName(FtpFilePath);
Response.ContentType = "application/" + _fname.Split('.')[1];
Response.AddHeader("Content-disposition", "attachment; filename=" + _fname);

byte[] buffer = new byte[10240];
int readCount;
do
{
    readCount = stream.Read(buffer, 0, buffer.Length);
    Response.OutputStream.Write(buffer, 0, readCount);//持續(xù)寫入流
} while (readCount != 0);

Response.OutputStream.Write(buffer, 0, buffer.Length);

Response.End();

string uri = "ftp://" + RemoteHost + "/" + fileName;
FtpWebRequest reqFTP;
reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + RemoteHost + "/" + fileName));

reqFTP.Credentials = new NetworkCredential(RemoteUser, RemotePass);
reqFTP.KeepAlive = false;
reqFTP.Method = WebRequestMethods.Ftp.DeleteFile;

string result = String.Empty;
FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
long size = response.ContentLength;
Stream datastream = response.GetResponseStream();
StreamReader sr = new StreamReader(datastream);
result = sr.ReadToEnd();
sr.Close();
datastream.Close();
response.Close();