急，ftp下载文件问题

mhjmhj2000 2006-12-05 01:17:54

string server = ftpip;
string username = ftpusername;
string password = ftppassword;
FtpWebRequest request =
(FtpWebRequest)WebRequest.Create(server);
request.Credentials = new NetworkCredential(username, password);
request.Method = WebRequestMethods.Ftp.ListDirectory;
response = (FtpWebResponse)request.GetResponse();
stream = response.GetResponseStream();

// 获取文件列表;
StreamReader reader = new StreamReader(stream);
string content = reader.ReadToEnd();
string[] files = content.Split('\n');
int s = files.Length;
reader.Close();

//下载列表文件
serverDirectory = null;
Uri baseUri = new Uri(server);

if (File.Exists(xmlad ))
{
File.Delete(@xmlad);
}
for (int i = 0; i <= s - 2; i++)
{
if (File.Exists(downaddress + @"\" + files[i]))
{

//i++;

}
else
{
string filename = files[i].ToString().Trim();
string fullFilename = serverDirectory + @"/" + filename;
Uri uri = new Uri(baseUri, fullFilename);
request = (FtpWebRequest)WebRequest.Create(uri);
request.Credentials = new NetworkCredential(username, password);
request.Method = WebRequestMethods.Ftp.DownloadFile;
response = (FtpWebResponse)request.GetResponse();
inStream = response.GetResponseStream();
// inStream.Length

File.Create(downaddress + filename);
outStream = File.OpenWrite(downaddress+ @"\" + filename);
byte[] buffer = new byte[1024];

int size = 0;
while ((size = inStream.Read(buffer, 0, 1024)) > 0)
{

outStream.Write(buffer, 0, size);
}
outStream.Flush();
outStream.Close();

}

用这段代码下载文件，如果文件已经存在，能否改写？

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