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How to retrieve/replace the Char Array in a class from database (SQL) [Answered]RSS

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Last post Jan 09, 2014 02:23 AM by Fuxiang Zhang - MSFT

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Mafullah

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3 Points

19 Posts

How to retrieve/replace the Char Array in a class from database (SQL)

Jan 07, 2014 08:34 PM|Mafullah|LINK

Hi master, please help me. I have a class there a char base64 index. so I want to dynamic from database. Here this class :

Imports System.Data
Imports System.Data.SqlClient
Namespace TestBase64
    ''' <summary>
    ''' Summary description for Base64Encoder.
    ''' </summary>
    Public Class Base64Encoder
        Private source As Byte()
        Private length As Integer, length2 As Integer
        Private blockCount As Integer
        Private paddingCount As Integer

     
        Public Sub New(input As Byte())
            source = input
            length = input.Length
            If (length Mod 3) = 0 Then
                paddingCount = 0
                blockCount = length \ 3
            Else
                paddingCount = 3 - (length Mod 3)
                'need to add padding
                blockCount = (length + paddingCount) \ 3
            End If
            'or blockCount *3
            length2 = length + paddingCount
        End Sub

        Public Function GetEncoded() As Char()
            Dim source2 As Byte()
            source2 = New Byte(length2 - 1) {}
            'copy data over insert padding
            For x As Integer = 0 To length2 - 1
                If x < length Then
                    source2(x) = source(x)
                Else
                    source2(x) = 0
                End If
            Next

            Dim b1 As Byte, b2 As Byte, b3 As Byte
            Dim temp As Byte, temp1 As Byte, temp2 As Byte, temp3 As Byte, temp4 As Byte
            Dim buffer As Byte() = New Byte(blockCount * 4 - 1) {}
            Dim result As Char() = New Char(blockCount * 4 - 1) {}
            For x As Integer = 0 To blockCount - 1
                b1 = source2(x * 3)
                b2 = source2(x * 3 + 1)
                b3 = source2(x * 3 + 2)

                temp1 = CByte((b1 And 252) >> 2)
                'first
                temp = CByte((b1 And 3) << 4)
                temp2 = CByte((b2 And 240) >> 4)
                temp2 += temp
                'second
                temp = CByte((b2 And 15) << 2)
                temp3 = CByte((b3 And 192) >> 6)
                temp3 += temp
                'third
                temp4 = CByte(b3 And 63)
                'fourth
                buffer(x * 4) = temp1
                buffer(x * 4 + 1) = temp2
                buffer(x * 4 + 2) = temp3

                buffer(x * 4 + 3) = temp4
            Next

            For x As Integer = 0 To blockCount * 4 - 1
                result(x) = sixbit2char(buffer(x))
            Next

            'covert last "A"s to "=", based on paddingCount
            Select Case paddingCount
                Case 0
                    Exit Select
                Case 1
                    result(blockCount * 4 - 1) = "="c
                    Exit Select
                Case 2
                    result(blockCount * 4 - 1) = "="c
                    result(blockCount * 4 - 2) = "="c
                    Exit Select
                Case Else
                    Exit Select
            End Select
            Return result
        End Function

        Private Function sixbit2char(b As Byte) As Char
            Dim lookupTable As Char() = New Char(63) {"A"c, "B"c, "C"c, "D"c, "E"c, "F"c, _
                "G"c, "H"c, "I"c, "J"c, "K"c, "L"c, _
                "M"c, "N"c, "O"c, "P"c, "Q"c, "R"c, _
                "S"c, "T"c, "U"c, "V"c, "W"c, "X"c, _
                "Y"c, "Z"c, "a"c, "b"c, "c"c, "d"c, _
                "e"c, "f"c, "g"c, "h"c, "i"c, "j"c, _
                "k"c, "l"c, "m"c, "n"c, "o"c, "p"c, _
                "q"c, "r"c, "s"c, "t"c, "u"c, "v"c, _
                "w"c, "x"c, "y"c, "z"c, "0"c, "1"c, _
                "2"c, "3"c, "4"c, "5"c, "6"c, "7"c, _
                "8"c, "9"c, "+"c, "/"c}

            If (b >= 0) AndAlso (b <= 63) Then
                Return lookupTable(CInt(b))
            Else
                'should not happen;
                Return " "c
            End If
        End Function
    End Class
End Namespace

The questions is how to retrieve or replace this code (char array) from database (sql) as example

        Dim lookupTable As Char() = New Char(63) {"A"c, "B"c, "C"c, "D"c, "E"c, "F"c, _
                "G"c, "H"c, "I"c, "J"c, "K"c, "L"c, _
                "M"c, "N"c, "O"c, "P"c, "Q"c, "R"c, _
                "S"c, "T"c, "U"c, "V"c, "W"c, "X"c, _
                "Y"c, "Z"c, "a"c, "b"c, "c"c, "d"c, _
                "e"c, "f"c, "g"c, "h"c, "i"c, "j"c, _
                "k"c, "l"c, "m"c, "n"c, "o"c, "p"c, _
                "q"c, "r"c, "s"c, "t"c, "u"c, "v"c, _
                "w"c, "x"c, "y"c, "z"c, "0"c, "1"c, _
                "2"c, "3"c, "4"c, "5"c, "6"c, "7"c, _
                "8"c, "9"c, "+"c, "/"c}

Please Help me,

Very Hope your answer and solutions.

Thank You, Master

- Reply
Fuxiang Zhan...

All-Star

30422 Points

3629 Posts
Re: How to retrieve/replace the Char Array in a class from database (SQL)

Jan 09, 2014 02:23 AM|Fuxiang Zhang - MSFT|LINK
Hi Mafullah,

From your class Base64Encoder, I see the method GetEncoded can convert the byte array to the chart array.

Then if you want to encode the data comes from database. I think you should read the data from database with the type Byte().

As my knowledge, sql server data type "binary" corresponding the type vb.net "Byte()". For this issue, you just read the Byte() data from database

to your application, then you can convert it like below.
```
Base64Encoder bec = new Base64Encoder(byteFromDatabase);
 char[] mychar= bec.GetEncoded();
```
If I misunderstand your issue, please feel free to back. Thanks.

Best Regards!
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