正在阅读：VisualBasic第三方控件实现软件在线升级VisualBasic第三方控件实现软件在线升级

Private Sub DL_DLBeginDownload()
　LogItem "开始下载从" & DL.FileURL
End Sub

Private Sub DL_DLCanceled()
　LogItem "取消下载"
End Sub

Private Sub DL_DLComplete(Bytes As Long) ’下载完成的事件
　cmdCancel.Enabled = False
　If Bytes > 0& Then ’如果下载的不是零字节，则显示相关信息
　　LogItem "完成" & SizeString(Bytes) & "下载并保存到" & DL.SaveFileName
　　’下面添加实现文件更新的代码
　　……
　Else
　　LogItem "下载失败"
　End If
End Sub

Private Sub DL_DLConnected(ConnAddr As String)
　LogItem "连接到 " & ConnAddr ’当连接成功时返回IP地址
End Sub

Private Sub DL_DLError(E As bkDLError, Error As String)
　Dim strErrType As String ’下载错误时的事件
　Select Case E
　　Case bkDLEUnavailable
　　　strErrType = "不可下载文件"
　　Case bkDLERedirect
　　　strErrType = "重定向"
　　Case bkDLEZeroLength
　　　strErrType = "没有字节返回"
　　Case bkDLESaveError
　　　strErrType = "文件保存错误"
　　Case bkDLEUnknown
　　　strErrType = "不明错误"
　End Select
　LogItem "错误 - " & strErrType & ": " & Error
End Sub

Private Sub DL_DLFileSize(Bytes As Long)
　’当连接后返回文件的大小，单位为字节，我们通过自定义的函数对单位进行必要转换
　LogItem "文件大小为" & SizeString(Bytes) & " (" & CStr(Bytes) & " bytes)"
End Sub

Private Sub DL_DLMIMEType(MIMEType As String)
　LogItem "MIME类型是 " & MIMEType
End Sub

Private Sub DL_DLProgress(Percent As Single, BytesRead As Long, TotalBytes As Long)
　’下载过程中的事件，返回下载百分比和已下载字节数。我们通过下面一行代码在lstOut中显示
　lblProg.Caption = Format(Percent, "0%") & " of " & SizeString(TotalBytes)
End Sub

Private Sub DL_DLRedirect(ConnAddr As String)
　’返回地址如果重定向　
　LogItem Index, "重定向到" & ConnAddr
End Sub

Private Sub LogItem(strItem As String)
　With lstOut
　　.AddItem "> " & strItem
　　If .NewIndex > .TopIndex + 17 Then
　　　.TopIndex = .NewIndex - 16
　　End If
　End With
End Sub

Private Function SizeString(lBytes As Long) As String
　If lBytes < &H400& Then
　　SizeString = CStr(lBytes) & "b"
　ElseIf lBytes < &H100000 Then
　　SizeString = CStr(lBytes \ 1024) & "k"
　ElseIf lBytes < &H20000000 Then
　　SizeString = Replace$(Format$((lBytes \ 1024) / 1024, "0.0"), ".0", vbNullString) & "M"
　Else
　　SizeString = Replace$(Format$((lBytes \ (1024 ^ 2)) / 1024, "#,##0.0"), ".0", vbNullString) & "G"
　End If
End Function