一个关于IP输入合法性的判断语句，请高手帮忙看看。运行出错。解决方案

一个关于IP输入合法性的判断语句，请高手帮忙看看。运行出错。。
代码如下：
Private Sub Command1_Click()
Dim Str1, Str2, Str3, Str4 As String
Dim s1, s2, s3, s4 As Integer
s1 = InStr(Text1.Text, ".") '获取小数点的位置
If s1 = 0 Then
MsgBox "输入地址不合法！请从新输入"
Str1 = Left(Text1.Text, s1 - 1) '截取小数点前面的字符
If Int(Str1) > 255 Or Int(Str1) < 0 Then '把字符换成整型做比较
MsgBox "输入地址不合法！请从新输入"
Else
s2 = InStr(Right(Text1.Text, Len(Text1.Text) - s1), ".") '获取从上一个小数点后下一个小数点的位置
If s2 = 0 Then
MsgBox "输入地址不合法！请从新输入"
Str2 = Left(Right(Text1.Text, Len(Text1.Text) - s1), s2 - 1) '截取从上一个小数点后下一个小数点前的字符
If Int(Str2) > 255 Or Int(Str2) < 0 Then
MsgBox "输入地址不合法！请从新输入"
Else
s3 = InStr(Right(Text1.Text, Len(Text1.Text) - s1 - s2), ".")
If s3 = 0 Then
MsgBox "输入地址不合法！请从新输入"
Str3 = Left(Right(Text1.Text, Len(Text1.Text) - s1 - s2), s3 - 1)
If Int(Str3) > 255 Or Int(Str3) < 0 Then
MsgBox "输入地址不合法！请从新输入"
Else
s4 = InStr(Right(Text1.Text, Len(Text1.Text) - s1 - s2 - s3), ".")
If s4 = 0 Then
MsgBox "输入地址不合法！请从新输入"
Str4 = Left(Right(Text1.Text, Len(Text1.Text) - s1 - s2 - s3), s4 - 1)
If Int(Str4) > 255 Or Int(Str4) < 0 Then
MsgBox "输入地址不合法！请从新输入"
Else
MsgBox "输入的地址合法！"
End If
Else
MsgBox "输入地址不合法！请从新输入"
End If
End If
End If
End If
End Sub


[解决办法]
给你改了下

VB code

Private Sub Command1_Click()Dim TmpA, i As ByteTmpA = Split(Text1.Text, ".")On Error GoTo ErrEIf UBound(TmpA) <> 3 Then GoTo ErrEFor i = 0 To 3    If Int(TmpA(i)) > 255 Or Int(TmpA(i)) < 0 Then GoTo ErrENextExit SubErrE: MsgBox "输入地址不合法！请从新输入"End Sub
[解决办法]
有那么复杂吗？
VB code
Function ChkIp(ip As String) As Boolean    Dim nrs() As String    ChkIp = False    If Len(Replace(ip, ".", "")) = (Len(ip) - 3) Then        nrs = Split(ip, ".")            If nrs(0) >= 256 Or nrs(1) >= 256 Or nrs(2) >= 256 Or nrs(3) >= 256 Then                ChkIp = False                Exit Function            End If    Else        ChkIp = False        Exit Function    End If    ChkIp = TrueEnd Function
[解决办法]
探讨

Split(Text1.Text, ".")
这个函数是什么意思。。。我刚学。。

[解决办法]
VB code
Option ExplicitFunction CheckIP(pStr As String) As Boolean  Dim tOutBool As Boolean  Dim tStringNums() As String  Dim tStringNums_Length As Long  Dim tStringNums_Index As Long  Dim tIPNum As Long    tStringNums() = Split(pStr, ".")  tStringNums_Length = UBound(tStringNums())    tOutBool = tStringNums_Length = 3    If tOutBool Then        For tStringNums_Index = 0 To tStringNums_Length            tOutBool = tOutBool And IsNumeric(tStringNums(tStringNums_Index))            If tOutBool Then                    tIPNum = CLng(tStringNums(tStringNums_Index))          tOutBool = tOutBool And (tIPNum >= 0) And (tIPNum <= 255)                Else                    Exit For            End If        Next    End If    CheckIP = tOutBoolEnd FunctionPrivate Sub Text1_Change()  Command1.Caption = CheckIP(Text1.Text)  Command1.Enabled = CheckIP(Text1.Text)End Sub
[解决办法]
VB code
Dim Text As String, IPStr As Variant, IP(3) As Byte, i As IntegerText = "192.168.1.1"IPStr = Split(Text, ".", 4)For i = 0 To 3    If Val(IPStr(i)) >= 0 And Val(IPStr(i)) <= 255 Then        IP(i) = IPStr(i)    Else        MsgBox "输入地址不合法！请从新输入"        Exit For    End IfNext