（VB）一个从字符串取出子字符串的函数

从字符串inString中取出在字符串sSpecString与nSpecString之间的子串

Function getSpecString(inString As String, sSpecString As String, nSpecString As String) As String
Dim subString As String
Dim sIndex As Long
Dim nIndex As Long
subString = ""

'当nSpecString <>"" ,即有指定第二个字符串的值
If nSpecString <> "" Then
    For sIndex = 1 To Len(inString)
        If Mid(inString, sIndex, Len(sSpecString)) = sSpecString Then
            For nIndex = sIndex To Len(inString)
                If Mid(inString, nIndex, Len(nSpecString)) = nSpecString Then
                    subString = Mid(inString, sIndex + Len(sSpecString), nIndex - sIndex - Len(sSpecString))
                    Exit For
                End If
            Next nIndex
        End If
    Next sIndex
Else

'如果nSpecString="",即取出sSpecString字符串以后所有的字符
    For sIndex = 1 To Len(inString)
        If Mid(inString, sIndex, Len(sSpecString)) = sSpecString Then
            subString = Mid(inString, sIndex + Len(sSpecString), Len(inString) - sIndex - Len(sSpecString))
            Exit For
        End If
    Next sIndex
End If

'判断取出的字符串是否有空行，如果有就删除
If InStr(subString, Chr(13) & Chr(10)) = 1 Then
    subString = Right(subString, Len(subString) - 2)
End If
getSpecString = subString

End Function

例如：inString = "Hello China!" ,sSpecString="He",nSpecString="a!"

Dim resultString As String

resultString = getSpecString(inString, sSpecString, nSpecString)

结果：resultString = "llo Chin"