Question

以下方法，我用来验证Base64

    Public Function ValidateBase64String(ByVal sString As String) As Boolean     
        If (sString.Length <> 4) Then
            Dim b As Byte() = Convert.FromBase64String(sString)
            Return True
        Else
            Return False
        End If
End Function

我将“johnjohn”作为字符串传递给方法，并且返回后面的字符串是base64字符串。是什么原因，而不是返回false，它返回true。

Answer 1

以下方法几乎每次都有效

    Console.WriteLine(ValidateBase64String("johnjohn"))-> it will always returns false

    Public Function ValidateBase64String(ByVal value As string) As Boolean
    Try
        If value.Length <> 4 AndAlso (Base64Decode(value) IsNot Nothing AndAlso System.Text.RegularExpressions.Regex.IsMatch(Base64Decode(value), "^[a-zA-Z0-9\+/]*={0,3}$")) Then
            Return True
        End If
    Catch ex As Exception            
    End Try
    Return False
End Function

Public Function Base64Decode(ByVal base64EncodedData As String) As String
    Try
        Dim base64EncodedBytes = System.Convert.FromBase64String(base64EncodedData)
        Return System.Text.Encoding.UTF8.GetString(base64EncodedBytes)
    Catch ex As Exception            
    End Try
    Return Nothing
End Function

检查字符串是否为Normal String或Base64 String问题

1 个答案: