try-catch-finally 变量作用域的问题 在线等
private void Download(string filePath, string fileName, string localfileName)
  {
  try
  {
  FtpWebRequest reqFTP;
  FileStream outputStream;
  FtpWebResponse response;
  Stream ftpStream;
  outputStream = new FileStream(filePath + "\\" + localfileName, FileMode.Create);
  reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + fileName));
  reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;
  reqFTP.UseBinary = true;
  reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
  response = (FtpWebResponse)reqFTP.GetResponse();
  ftpStream = response.GetResponseStream();
  long cl = response.ContentLength;
  int bufferSize = 2048;
  int readCount;
  byte[] buffer = new byte[bufferSize];
  readCount = ftpStream.Read(buffer, 0, bufferSize);
  while (readCount > 0)
  {
  outputStream.Write(buffer, 0, readCount);
  readCount = ftpStream.Read(buffer, 0, bufferSize);
  }
  }
  catch (Exception ex)
  {
  //Console.WriteLine(ex.Message());
  }
  finally
  {
  ftpStream.Close();
  outputStream.Close();
  response.Close();
  }
  }

为什么编译之后 finally中 的三个要关闭的资源变量报错 提示ftpStream,outputStream,response未定义.
如果放到把定义这三个对象放在try上面 就说未附值.
难道在try中定义的变量或者对象 作用域只在try 中吗 ?

------解决方案--------------------
private void Download(string filePath, string fileName, string localfileName) 
{ 
FileStream outputStream;
FtpWebResponse response;
Stream ftpStream;
try 
{ 
FtpWebRequest reqFTP; 

outputStream = new FileStream(filePath + "\\" + localfileName, FileMode.Create); 
reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + fileName)); 
reqFTP.Method = WebRequestMethods.Ftp.DownloadFile; 
reqFTP.UseBinary = true; 
reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword); 
response = (FtpWebResponse)reqFTP.GetResponse(); 
ftpStream = response.GetResponseStream(); 
long cl = response.ContentLength; 
int bufferSize = 2048; 
int readCount; 
byte[] buffer = new byte[bufferSize]; 
readCount = ftpStream.Read(buffer, 0, bufferSize); 
while (readCount > 0) 
{ 
outputStream.Write(buffer, 0, readCount); 
readCount = ftpStream.Read(buffer, 0, bufferSize); 
} 
} 
catch (Exception ex) 
{ 
//Console.WriteLine(ex.Message()); 
} 
finally 
{ 
ftpStream.Clo