以下截自某.BAS文件

End Sub

Private Sub Main()
Dim strTemp As String
Dim ret As Long
Dim n As Integer

Screen.MousePointer = vbHourglass
DoEvents

strTemp = Environ$("PressID")
Select Case Len(strTemp)
    Case 0
        strPressID = "P000"
    Case 1
        strPressID = "P0" & strTemp
    Case 2, 3
        strPressID = "P" & strTemp
End Select
strLogFileName = App.Path & Replace$(strPressID, "P", "\Press") & ".log"

'    strLogFileName = App.Path & "\Press" & Mid$(strPressID, 2, 3) & ".log"


strFactory = UCase$(GetSetting(App.Title, "GlobalConstant", "Factory", "AUBU"))
If strFactory <> "MIENT" Then strFactory = "AUBU"
SaveSetting App.Title, "GlobalConstant", "Factory", strFactory

User_Message vbNullString, FILE_MESSAGE
If App.PrevInstance = True Then
    User_Message "Previous Instance of programm is loaded, programm terminated", FILE_MESSAGE
    End
Else
'    If Len(Dir(strLogFileName)) <> 0 Then
'        If FileLen(strLogFileName) > 24000 Then             ' max size of log-file 24 KByte
'            If Len(Dir$(App.Path & "\log_old.txt")) <> 0 Then Kill App.Path & "\log_old.txt"
'            Name strLogFileName As App.Path & "\log_old.txt"
'        End If
'    End If
   

烦请各位高手帮忙解释一下 十分感谢！

Private Sub Main()
Dim strTemp As String
Dim ret As Long
Dim n As Integer

Screen.MousePointer = vbHourglass    '好像是设置鼠标形状，没VB在这里，没法查
DoEvents

strTemp = Environ$("PressID")        '调用函数
Select Case Len(strTemp)             '根据返回值的长度,生成一个变量值
    Case 0
        strPressID = "P000"
    Case 1
        strPressID = "P0" & strTemp
    Case 2, 3
        strPressID = "P" & strTemp
End Select
strLogFileName = App.Path & Replace$(strPressID, "P", "\Press") & ".log"    '日志文件名

'    strLogFileName = App.Path & "\Press" & Mid$(strPressID, 2, 3) & ".log"


strFactory = UCase$(GetSetting(App.Title, "GlobalConstant", "Factory", "AUBU"))  '读INI文件,
If strFactory <> "MIENT" Then strFactory = "AUBU"        '设置必须为mient 或 aubu
SaveSetting App.Title, "GlobalConstant", "Factory", strFactory    '写INI文件

User_Message vbNullString, FILE_MESSAGE       '调用函数
If App.PrevInstance = True Then               '忘了,要查VB
    User_Message "Previous Instance of programm is loaded, programm terminated", FILE_MESSAGE   '调用函数
    End        '结束程序
Else
'    If Len(Dir(strLogFileName)) <> 0 Then                    '测试文件是否存在
'        If FileLen(strLogFileName) > 24000 Then             ' max size of log-file 24 KByte   '文件是否大于
'            If Len(Dir$(App.Path & "\log_old.txt")) <> 0 Then Kill App.Path & "\log_old.txt"   '如果旧文件存在那么删除掉
'            Name strLogFileName As App.Path & "\log_old.txt"       '把现在的日志文件改名为 old
'        End If
'    End If

先感谢兄弟了  我发这段代码的目的是因为一台设备用VB编写的工控软件和PLC通讯 赋值给PLC存储器 0值代表选择AUBU 1值代表选择MIENT   我试图通过这段代码来发现时什么条件决定输出0或者1 因为软件的界面并没有选项 在您的回复中 您可能也看到了 设置必须为mient 或 aubu