函数的optional 参数报错

sdyaojingwen

最近想做一个截取两个字符之间的字符串的函数对于第二个函数
Public Function interceptStrinTwoChars(findChar1 As String, seq1 As Integer, findchar2 As String, seq2 As Integer, withinStr As String, Optional trimFlag As Boolean = True) As String
想把seq1和seq2改成默认为1,如下所示会报错
Public Function interceptStrinTwoChars(findChar1 As String, Optional seq1 As Integer = 1,findchar2 as String,optional seq2 as Integer =1,withinstr as String,optional trimFlag as Boolean=True) as String  能帮忙看下错在哪里了么
'得到一个字符串中第n个字符所在的位置的位置
'比如说要得到第二个空格的位置myInstr(" ",2,"how are  you",)
'比如说要得到倒数第二个空格的位置 myInstr("",-2,"how are  you ")

Public Function myInstr(findstr As String, n As Integer, withinStr As String) As Integer
Dim i, m As Integer
If n > 0 Then
    m = InStr(withinStr, findstr)
    While n > 1
        m = InStr(m + 1, withinStr, findChar)
        n = n - 1
    Wend
Else

    m = InStrRev(withinStr, findstr)
    While n < -1
       m = InStrRev(withinStr, findstr, m - 1)
       n = n + 1
    Wend
End If
myInstr = m
End Function




Public Function interceptStrinTwoChars(findChar1 As String, seq1 As Integer, findchar2 As String, seq2 As Integer, withinStr As String, Optional trimFlag As Boolean = True) As String
Dim start, lenth As Integer
    start = myInstr(findChar1, seq1, withinStr) + 1
    lenth = myInstr(findchar2, seq2, withinStr) - myInstr(findChar1, seq1, withinStr) - 1
    If trimFlag = True Then
        interceptStrinTwoChars = Trim(Mid(withinStr, start, lenth))
    Else
        interceptStrinTwoChars = Mid(withinStr, start, lenth)
    End If
End Function

opiona

Optional  参数要放在正常参数后面
Optional  参数后面只能是： Optional  参数

sdyaojingwen

opiona 发表于 2018-7-18 10:03
Optional  参数要放在正常参数后面
Optional  参数后面只能是： Optional  参数

像instr这种 第一个参数start反而是可选的是咋实现的呢?

sdyaojingwen

opiona 发表于 2018-7-18 10:03
Optional  参数要放在正常参数后面
Optional  参数后面只能是： Optional  参数

改完确实好了!!感谢!!