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

• • Reply
  Mafullah

  Member

  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

  30411 Points

  3628 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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