用charindex加reverse应可以实现你所要的所有功能

LS的不要亂搞

Dim a As String
    a = "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\NoDriveTypeAutoRun"
    MsgBox Right(a, Len(a) - InStrRev(a, "\"))

InStr函數是從左邊開始找
InStrRev函數是從右邊開始找

老兄,你要思考
例如說HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\NoDriveTypeAutoRun
你要得到第3個吧
Dim a As String
Dim i As String
    a = "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\NoDriveTypeAutoRun"
'    MsgBox Right(a, Len(a) - InStrRev(a, "\"))
   
    i = 1
    Do While i < 3
        a = Right(a, Len(a) - InStr(a, "\"))
        i = i + 1
    Loop
    MsgBox Left(a, InStr(a, "\") - 1)

Do While i < 3(如果你要取第四個,把這裡3改成4)

感谢随风逐流，也帮了我一大忙。。。

  Dim STR1 As String
  Dim I As Long, J As Long
  
  STR1 = "HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Policies\Explorer\NoDriveTypeAutoRun"
  I = InStr(STR1, "\") + 1
  If I > 1 Then
    J = InStrRev(STR1, "\")
    If J Then Debug.Print Mid(STR1, I, J - I)
  End If