VB自定义加解密函数运行提示argument not optional错误如何解决？

报错argument not optional的解决 #

你定义的CleanEncryptSTR函数包含3个必传参数：待处理字符串、密码、加解密标识布尔值，调用时缺传任意一个都会触发该错误。
正确调用示例：

• 加密操作：CleanEncryptSTR("待加密内容", "自定义密码", True)
• 解密操作：CleanEncryptSTR("待解密内容", "和加密一致的密码", False)

满足「字符类型不变」需求的代码修正 #

原代码问题：AllowedChars集合包含&、;两个符号，且将数字、大小写字母放在同一集合做偏移运算，会导致数字加密后变为字母、字母加密后变为符号，不符合你的需求。
以下是修正后的完整代码，将三类合法字符拆分处理，保证加密后数字仍为数字、大写字母仍为大写字母、小写字母仍为小写字母，不在三类范围内的字符原样保留：

Public Function CleanEncryptSTR(MyString As String, MyPassword As String, Encrypt As Boolean) As String
' Encrypt True: 加密   False: 解密
    Dim i As Integer
    Dim ASCToAdd As Integer
    Dim ThisChar As String
    Dim ThisASC As Integer
    Dim NewASC As Integer
    Dim MyStringEncrypted As String
    ' 拆分三类字符池，独立处理
    Dim NumChars As String, UpperChars As String, LowerChars As String
    Dim PoolLength As Integer, CurrentPool As String
    
    NumChars = "0123456789"
    UpperChars = "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    LowerChars = "abcdefghijklmnopqrstuvwxyz"

    If Len(MyPassword) > 0 Then
        For i = 1 To Len(MyString)
            ThisChar = Mid(MyString, i, 1)
            ' 判断当前字符所属的字符池
            ThisASC = InStr(NumChars, ThisChar)
            If ThisASC > 0 Then
                PoolLength = Len(NumChars)
                CurrentPool = NumChars
            Else
                ThisASC = InStr(UpperChars, ThisChar)
                If ThisASC > 0 Then
                    PoolLength = Len(UpperChars)
                    CurrentPool = UpperChars
                Else
                    ThisASC = InStr(LowerChars, ThisChar)
                    If ThisASC > 0 Then
                        PoolLength = Len(LowerChars)
                        CurrentPool = LowerChars
                    Else
                        ' 不在合法字符池内，原样保留
                        MyStringEncrypted = MyStringEncrypted & ThisChar
                        GoTo NextLoop
                    End If
                End If
            End If
            
            ' 偏移计算逻辑和原设计保持一致
            ASCToAdd = Asc(Mid(MyPassword, i Mod Len(MyPassword) + 1, 1))
            If Encrypt Then
                NewASC = ThisASC + ASCToAdd
            Else
                NewASC = ThisASC - ASCToAdd
            End If
            NewASC = NewASC Mod PoolLength
            If NewASC <= 0 Then
                NewASC = NewASC + PoolLength
            End If

            MyStringEncrypted = MyStringEncrypted & Mid(CurrentPool, NewASC, 1)
NextLoop:
        Next i
    Else
        MyStringEncrypted = MyString
    End If

    CleanEncryptSTR = MyStringEncrypted
End Function

修正说明：

• 拆分三类独立字符池，每个字符仅在所属池内做偏移运算，不会跨类型跳转
• 保留原有的密码流偏移逻辑，加解密规则和原设计完全兼容
• 过滤了原代码中的符号字符，不会出现加密后输出符号的问题

内容的提问来源于stack exchange，提问作者TestingGroundz