C＃FtpWebRequest文件版本检查

Question

我正在尝试使用C＃FtpWebRequest下载文件。除非下载站点中的文件版本大于当前文件版本，否则我不想下载。如何在远程服务器上验证/获取文件版本？

Answer 1

Only .exe and .dll files have version info, which can be read by using
FileVersionInfo..::.GetVersionInfo(). Text files do not have version info. 
Also, in order to read this version info, you'll have to download the file 
to a temp location.


Alternately, you can use the LastModifiedDate of the file to check if it is more 
recent. That will work for any type of file and can be done directly at the FTP 
site w/o downloading the file:

string requestUriString = BuildRequestUriString(ServerName, Path, fileName);
FtpWebRequest aRequest = (FtpWebRequest) WebRequest.Create(requestUriString)
aRequest.Method = WebRequestMethods.Ftp.GetDateTimestamp;
...

using (FtpWebResponse aResponse = (FtpWebResponse) aRequest.GetResponse())
{
  return aResponse.LastModified;
}