使用FtpWebRequest取得FTP檔案時，使用StreamReader處理FtpWebResponse的內容，有時候會出現「無法存取已處置物件」錯誤。
發生錯誤的寫法是使用While (Not StreamReader.EndOfStream)逐一讀取每行文字，理當在讀取最後一行後結束，大致如下：
'Download file by text
Public Sub FtpDownLoadTextFile(ByVal str_FtpAccount As String,
ByVal str_FtpPassword As String,
ByVal str_FtpAddress As String)
Dim ftp_Request As FtpWebRequest = Nothing
Dim strlst_EachLine As New List(Of String)
Dim str_Line As String = String.Empty
ftp_Request = CType(WebRequest.Create(str_FtpAddress), FtpWebRequest)
ftp_Request.Credentials = New NetworkCredential(str_FtpAccount, str_FtpPassword)
ftp_Request.Method = WebRequestMethods.Ftp.DownloadFile
Using ftp_Response As FtpWebResponse = DirectCast(ftp_Request.GetResponse(), FtpWebResponse)
Using ftp_StreamReader As New StreamReader(ftp_Response.GetResponseStream)
While (Not ftp_StreamReader.EndOfStream)
str_Line = ftp_StreamReader.ReadLine
End While
End Using
End Using
End Sub但是偶爾會在讀取到最後時出現「無法存取已處置物件」錯誤。
後來發現是文字檔最後沒有多一行，也就是換行+歸位（chr10+chr13），所以之後FTP下載文字檔統一改用StreamReader.ReadToEnd，將內容一次讀出然後再分行。由於曾經碰過檔案只寫chr10但是沒有chr13的情況，所以我最後將chr10+chr13、chr10、chr13視為三種分行情況。
'Download file by text
Public Function str_FtpDownLoadTextFile(ByVal str_FtpAccount As String,
ByVal str_FtpPassword As String,
ByVal str_FtpAddress As String) As String
Dim ftp_Request As FtpWebRequest = Nothing
Dim strlst_EachLine As New List(Of String)
Dim str_Line As String = String.Empty
ftp_Request = CType(WebRequest.Create(str_FtpAddress), FtpWebRequest)
ftp_Request.Credentials = New NetworkCredential(str_FtpAccount, str_FtpPassword)
ftp_Request.Method = WebRequestMethods.Ftp.DownloadFile
Using ftp_Response As FtpWebResponse = DirectCast(ftp_Request.GetResponse(), FtpWebResponse)
Using ftp_StreamReader As New StreamReader(ftp_Response.GetResponseStream)
str_Line = ftp_StreamReader.ReadToEnd
End Using
End Using
Return str_Line
End Function
'Saperate text file to each line
Public Function strary_SeparateFtpTextFile(ByVal str_FtpAccount As String,
ByVal str_FtpPassword As String,
ByVal str_FtpAddress As String) As String()
Dim strary_SeparatedTextFile() As String
Dim str_TextContent As String
str_TextContent = str_FtpDownLoadTextFile(str_FtpAccount, str_FtpAccount, str_FtpAddress)
If str_TextContent.Contains(vbCrLf) Then
strary_SeparatedTextFile = Split(str_TextContent, vbCrLf)
ElseIf str_TextContent.Contains(vbCr) Then
strary_SeparatedTextFile = Split(str_TextContent, vbCr)
ElseIf str_TextContent.Contains(vbLf) Then
strary_SeparatedTextFile = Split(str_TextContent, vbLf)
Else
strary_SeparatedTextFile = {str_TextContent}
End If
Return strary_SeparatedTextFile
End Function