C#实现文件下载(转载)

private bool DownLoad(string downloadUrl,string savepath)
{
Stream responseStream = null;
FileStream fileStream = null;
StreamReader reader = null;
try
{
FtpWebRequest downloadRequest =(FtpWebRequest)WebRequest.Create(downloadUrl);
downloadRequest.Credentials = new NetworkCredential(txtuser.Text.Trim(), txtpwd.Text.Trim());
FtpWebResponse downloadResponse =(FtpWebResponse)downloadRequest.GetResponse();
responseStream = downloadResponse.GetResponseStream();
string fileName =Path.GetFileName(downloadRequest.RequestUri.AbsolutePath);

if (fileName.Length == 0)
{
reader = new StreamReader(responseStream);
Console.WriteLine(reader.ReadToEnd());
}
else
{
fileStream = File.Create(savepath+fileName);
byte[] buffer = new byte[1024];
int bytesRead;
while (true)
{
bytesRead = responseStream.Read(buffer, 0, buffer.Length);
if (bytesRead == 0)
break;
fileStream.Write(buffer, 0, bytesRead);
}
}
return true;
}
catch (UriFormatException ex)
{
MessageBox.Show(ex.Message);
return false;
}
catch (WebException ex)
{
MessageBox.Show(ex.Message);
return false;
}
catch (IOException ex)
{
MessageBox.Show(ex.Message);
return false;
}
finally
{
if (reader != null)
reader.Close();
else if (responseStream != null)
responseStream.Close();
if (fileStream != null)
fileStream.Close();
}
}