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你好再次StackOverflow社區！VB.Net線程和Addhandler問題
我正在研究「SendLogfileClass」類。在這堂課中，我通過電子郵件發送一個日誌文件到所述電子郵件帳戶該部分按預期工作。我遇到的問題是試圖處理異步完成事件。在所述事件期間，Addhandler觸發並在主窗體上設置StatusBar.StatusLabel。
下面是一些代碼相關的塊：
#Region "Imports"
Imports System
Imports System.Net
Imports System.Net.Mail
Imports System.Net.Mime
Imports System.Threading
Imports System.ComponentModel
Imports System.IO
#End Region
Public Class Form1
#Region "Public"
Private SendmailThread As Thread
Private MailBody As String = Nothing
#End Region
#Region "Private"
Private mailSent As Boolean = False
#End Region
Public Function GetTimestamp() As String
Dim t As Date = Date.Now
Dim timestamp As String = Nothing
Try
timestamp = t.ToLongTimeString & " " & t.ToLongDateString
Catch ex As Exception
Return 1
End Try
Return timestamp
End Function
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Try
If LoggerClock.Enabled = True Then
OutputConsole.Text = "logger Started: " & GetTimestamp() & vbNewLine
OutputConsole.AppendText("Logfile Opened: " & GetTimestamp() & vbNewLine)
StatusLabel.Text = "Logger Status: Active"
StatusBar.Refresh()
Else
OutputConsole.Text = "logger Started: " & GetTimestamp() & vbNewLine
StatusLabel.Text = "Logger Status: Inactive"
StatusBar.Refresh()
End If
SendlogClock.Enabled = True
ToggleViewForm(1)
Catch ex As Exception
Exit Sub
End Try
End Sub
Public Function SetStatus(ByVal [status] As String) As Integer
Try
Thread.Sleep(1000)
StatusLabel.Text = [status]
StatusBar.Refresh()
Catch ex As Exception
Return 1
End Try
Return 0
End Function
Private Sub SendlogThreadTask()
Try
SendLogfile("[email protected]", "Logger Logfile", MailBody).ToString()
Catch ex As Exception
Exit Sub
End Try
End Sub
Private Sub SendlogClock_Tick(sender As Object, e As EventArgs) Handles SendlogClock.Tick
Try
OutputConsole.AppendText("Logfile Closed: " & GetTimestamp() & vbNewLine)
SendmailThread = New Thread(AddressOf SendlogThreadTask)
SendmailThread.IsBackground = True
SendmailThread.Start()
OutputConsole.ResetText()
OutputConsole.Text = "Logfile Opened: " & GetTimestamp() & vbNewLine
Catch ex As Exception
Exit Sub
End Try
End Sub
Public Sub SendCompletedCallback(ByVal sender As Object, ByVal e As AsyncCompletedEventArgs)
Try
' Get the unique identifier for this asynchronous operation.
Dim token As String = CStr(e.UserState)
If e.Cancelled Then
StatusLabel.Text = "Send Canceled... " & token
StatusBar.Refresh()
End If
If e.Error IsNot Nothing Then
StatusLabel.Text = "Error: " & token & " " & e.Error.ToString() & " "
StatusBar.Refresh()
Else
StatusLabel.Text = "Message Sent... "
StatusBar.Refresh()
End If
mailSent = True
Catch ex As Exception
Exit Sub
End Try
End Sub
Public Function SendLogfile(ByVal mailTo As String, ByVal mailSubject As String, ByVal mailBody As String, Optional ByVal doAttach As Boolean = False, Optional ByVal messageAttach As String = Nothing) As Integer
Try
' SMTP Server
Dim SmtpServer As String = "mail.domain.com"
' Command line argument must the the SMTP host.
Dim Cli As New SmtpClient(SmtpServer)
' Specify the e-mail sender.
' Create a mailing address that includes a UTF8 character
' in the display name.
Dim [from] As New MailAddress("[email protected]", "logger " & ChrW(&HD8) & " logs", System.Text.Encoding.UTF8)
' Set destinations for the e-mail message.
Dim [to] As New MailAddress(mailTo)
' Specify the message content.
Dim message As New MailMessage([from], [to])
message.Body = mailBody
' Include some non-ASCII characters in body and subject.
Dim someArrows As New String(New Char() {ChrW(&H2190), ChrW(&H2191), ChrW(&H2192), ChrW(&H2193)})
message.Body += Environment.NewLine & someArrows
message.BodyEncoding = System.Text.Encoding.UTF8
message.Subject = mailSubject & someArrows
message.SubjectEncoding = System.Text.Encoding.UTF8
' Put the mail attachment in a list of items
'Dim attachment As New Attachment(messageAttach)
' Attach file.
'If doAttach = True Then
'If File.Exists(messageAttach) Then
'message.Attachments.Add(attachment)
'End If
'End If
' Set the method that is called back when the send operation ends.
AddHandler Cli.SendCompleted, AddressOf SendCompletedCallback
' The userState can be any object that allows your callback
' method to identify this send operation.
' For this example, the userToken is a string constant.
Dim userState As String = "OK"
Cli.SendAsync(message, userState)
'MsgBox("Sending message... press c to cancel mail. Press any other key to exit.")
Dim answer As String = "OK" ' or CANCEL
' If the user canceled the send, and mail hasn't been sent yet,
' then cancel the pending operation.
If answer.StartsWith("C") AndAlso mailSent = False Then
Cli.SendAsyncCancel()
End If
' Clean up.
message.Dispose()
Catch ex As Exception
MsgBox("Encountered Error: " & vbNewLine & vbNewLine & ex.ToString())
Return 1
End Try
Return 0
End Function
End Class
我加入了同一個應用程序的簡化的單級版本，請你給我如何完成所需任務的例子嗎？ –