Question

我遇到了一个问题，我真的无法理解它。我查看了各种可能的解决方案，实现了不同的代码片段，包括来自MSDN的代码片段。不幸的是，所有的解决方案都只是在我的问题上跳舞，经过几个小时的黑客攻击后，我终于离开了SOF大道。

我正在尝试从多维ArrayList中检索信息（POP3邮件列表）。以下代码创建ArrayList。我还在调试模式期间添加了ArrayList的值。

'*******************************************************************************
' Function Name : List
' Credit to     : David Ross Goben
' Purpose       : Get the drop listing from the maildrop
'               :
' Returns       : Any Arraylist of POP3Message objects
'               :
' Typical telNet I/O:
'LIST            (submit)
'+OK Mailbox scan listing follows
'1 2532          (record index and size in bytes)
'2 1610
'3 12345
'.               (end of records terminator)
'*******************************************************************************
Public Function List() As ArrayList
    If Not IsConnected() Then Return Nothing '          'exit if not in TRANSACTION mode

    Me.Submit("LIST" & vbCrLf)                          'submit List request
    If Not CheckResponse() Then Return Nothing '        'check for a response, but if an error, return nothing
    '
    'get a list of emails waiting on the server for the authenticated user
    '
    Dim retval As New ArrayList                       'set aside message list storage
    Do
        Dim response As String = Me.Response            'check response
        If (response = "." & vbCrLf) Then               'done with list?
            Exit Do                                     'yes
        End If
        Dim msg As New POP3Message                      'establish a new message
        Dim msgInfo() As String = Split(response, " "c) 'separate by spaces, which divide its fields
        msg.MailID = Integer.Parse(msgInfo(0))          'get the list item number
        msg.ByteCount = Integer.Parse(msgInfo(1))       'get the size of the email message
        msg.Retrieved = False                           'indicate its message body is not yet retrieved
        retval.Add(msg)                                 'add a new entry into the retrieval list
    Loop
    Return retval                                       'return the list
End Function

不幸的是，我无法在调试模式下发布数据的图像，但我会尝试使用它的文本表示：

'List  | Count = 125                        
'    |
'   (0) | Nothing
'   (1) | Nothing
'            |
'       Mail.POP3Message | Nothing
'                |
'           ByteCount | 492334
'           MailID    | 1
'           Message   | Nothing
'           Retrieved | False

当我检查列表中是否有任何项目时，它会返回有效的项目数。

'Get message list from pop3 server and populate dvgMsgList
        dgvMailSettings.Rows(12).Cells(1).Value = "retrieving LIST of messages"


        Try
            For Each msg In srvPOP3.List
                MsgBox("srvPOP3.List items = " & srvPOP3.List.Count)
            Next

        Catch ex As Exception
            MsgBox(ex.Message, MsgBoxStyle.Information, "Error displaying Mail list")
        End Try

如果有人可以为我阐明这个主题，我真的很感激，因为我真的需要了解这些数据：

          |
       ByteCount   | 492334
       MailID      | 1
       Message     | Nothing
       Retrieved   | False

（我只对前两项感兴趣）

从多维ArrayList中检索信息

0 个答案: