跳过错误的计算机

Question

我在使用 VBScript 时遇到问题，它从 Excel 工作表上的列表中查找计算机上的打印机，然后通过 WMI 找到它们。它通过 IP 地址名称匹配它们，然后编写一个批处理文件，我可以从中安装它们。我的问题是，当我关闭计算机时，我收到一个 462 错误，然后将其清除，但随后再次写入前一台计算机的打印机。我对此很陌生，所以我不确定我是否只是在这里遗漏了一些非常基本的东西。

Batch = "printerOutput.txt"
Const ForWriting = 2 'Set to 8 for appending data
Set objFSO = CreateObject("Scripting.FileSystemObject")
Set objFile = objFSO.OpenTextFile(Batch, ForWriting)

On Error Resume Next

Dim printerDictionary 'Create Printer dictionary of names and IP addresses
        Set printerDictionary = CreateObject("Scripting.Dictionary")
            printerDictionary.Add "Printer","xxx.xxx.xxx.xxx"


Set objExcel_1 = CreateObject("Excel.Application")
' Statement will open the Excel Workbook needed.

Set objWorkbook = objExcel_1.Workbooks.Open _
("x\p.xls")

If Err.Number <> 0 Then
    MsgBox "File not Found"
    Wscript.Quit

End If
'Checks for errors
f = 1 'Sets variable that will loop through Excel column


Do

' Msgbox f,, "Begining of Do Loop"


    strComputer = objExcel_1.Cells(f, 1).Value
    Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")      
    Set colPrinters = objWMIService.ExecQuery("Select * From Win32_Printer")
    For Each objPrinter in colPrinters 'For ever objPrinter found in the computers WMIService


    If Err.Number = 0 Then

            objFile.WriteLine Err.Number
            If InStr(ObjPrinter.PortName,".") = 4 then 'If the printers IP port name is written like 128.xxx.xxx.xxx

                'MsgBox ObjPrinter.Name & " " & ObjPrinter.PortName,, "IfStatement"
                PrtDict ObjPrinter.PortName, StrComputer

            ElseIf InStr(ObjPrinter.PortName,"_") = 3 Then 'If the printers IP port name is written like IP_128.xxx.xxx.xxx
                cleanIP = GetIPAddress(objPrinter.PortName) 'Clean IP

                PrtDict cleanIP, StrComputer        
            End If

    Else

        objFile.WriteLine "REM " & strComputer & " - Error:  " & err.number
        Err.Clear

    End If

    Next



    f = f + 1


Loop Until objExcel_1.Cells(f, 1).Value = ""

objExcel_1.ActiveWorkbook.Close
ObjExcel_1.Quit

Function PrtDict(PrtMn, CMP) 'Loops through the dictionary to find a match from the IP address found


        For Each x in printerDictionary
            'MsgBox PrtMn & "=" & printerDictionary.Item(x),,"InPtrDict"
            If printerDictionary.Item(x) = PrtMn Then

                objFile.WriteLine "psexec -u \%1 -p %2 " & CMP & " path\" & x & ".bat"

            End If
        Next

End Function
'100
Function GetIPAddress(Address) 'For cleaning up IP address with names like IP_128.xxx.xxx.xxx

    IPtext = InStr(Address,"_")
    IPaddress = len(Address) - IPtext

GetIPAddress = Right(Address,IPaddress)
End Function

Answer 1

会发生什么：

1. On Error Resume Next

   这将为脚本的其余部分启用错误处理（或者更确切地说是错误抑制），因为它从未被禁用。

2. Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")

   此命令失败，因为无法访问strComputer。由于错误，设置了变量 Err 并且 objWMIService 保留其先前的值。

3. Set colPrinters = objWMIService.ExecQuery("Select * From Win32_Printer")

   此命令成功并从前一台计算机重新读取打印机列表，因为objWMIService 仍然指的是那台计算机。

4. For Each objPrinter in colPrinters

   脚本进入循环，因为colPrinters 被前一台计算机的打印机（再次）填充，......

5. If Err.Number = 0 Then ... Else ... End If

   ...但是因为Err仍然设置，脚本进入Else分支，在那里报告并清除错误：

   objFile.WriteLine "REM " & strComputer & " - Error:  " & err.number
   Err.Clear
   

6. 然后脚本进入循环的下一个迭代。 Err 现已被清除，因此colPrinters 中的其余打印机正在正常处理中。

全球On Error Resume Next是万恶之源。不要这样做。 永远。

如果您绝对必须使用On Error Resume Next，请在本地启用错误处理，放置一些实际的错误处理代码，然后立即禁用错误处理。在您的情况下，可能会像这样实现它：

...
Do
  strComputer = objExcel_1.Cells(f, 1).Value
  On Error Resume Next
  Set objWMIService = GetObject("winmgmts:\\" & strComputer & "\root\cimv2")
  If Err Then
    objFile.WriteLine "REM " & strComputer & " - Error:  " & err.number
    Set objWMIService = Nothing
  End If
  On Error Goto 0

  If Not objWMIService Is Nothing Then
    Set colPrinters = objWMIService.ExecQuery("Select * From Win32_Printer")
    For Each objPrinter in colPrinters
      ...
    Next
    f = f + 1
  End If
Loop Until objExcel_1.Cells(f, 1).Value = ""
...