VB.NET Convert.FromBase64CharArray方法代碼示例

Public Sub DecodeWithCharArray()
   Dim inFile As System.IO.StreamReader
   Dim base64CharArray() As Char

   Try
      inFile = New System.IO.StreamReader(inputFileName, _
                                          System.Text.Encoding.ASCII)

      ReDim base64CharArray(inFile.BaseStream.Length - 1)
      inFile.Read(base64CharArray, 0, inFile.BaseStream.Length)
      inFile.Close()
   Catch exp As System.Exception
      ' Error creating stream or reading from it.
      System.Console.WriteLine("{0}", exp.Message)
      Return
   End Try

   ' Convert the Base64 UUEncoded input into binary output.
   Dim binaryData() As Byte
   Try
      binaryData = System.Convert.FromBase64CharArray(base64CharArray, 0, _
                                                base64CharArray.Length)
   Catch exp As System.ArgumentNullException
      System.Console.WriteLine("Base 64 character array is null.")
      Return
   Catch exp As System.FormatException
      System.Console.WriteLine("Base 64 Char Array length is not " + _
               "4 or is not an even multiple of 4")
      Return
   End Try

   ' Write out the decoded data.
   Dim outFile As System.IO.FileStream
   Try
      outFile = New System.IO.FileStream(outputFileName, _
                                         System.IO.FileMode.Create, _
                                         System.IO.FileAccess.Write)
      outFile.Write(binaryData, 0, binaryData.Length - 1)
      outFile.Close()
   Catch exp As System.Exception
      ' Error creating stream or writing to it.
      System.Console.WriteLine("{0}", exp.Message)
   End Try
End Sub

' This example demonstrates the Convert.ToBase64CharArray() and 
'                               Convert.FromBase64CharArray methods
Class Sample
   Public Shared Sub Main()
      Dim byteArray1(255) As Byte
      Dim byteArray2(255) As Byte
      Dim charArray(351) As Char
      Dim charArrayLength As Integer
      Dim nl As String = Environment.NewLine
      
      Dim ruler1a As String = "         1         2         3         4"
      Dim ruler2a As String = "1234567890123456789012345678901234567890"
      Dim ruler3a As String = "----+----+----+----+----+----+----+----+"
      Dim ruler1b As String = "         5         6         7      "
      Dim ruler2b As String = "123456789012345678901234567890123456"
      Dim ruler3b As String = "----+----+----+----+----+----+----+-"
      Dim ruler As String = String.Concat(ruler1a, ruler1b, nl, _
                                          ruler2a, ruler2b, nl, _
                                          ruler3a, ruler3b)

      ' 1) Initialize and display a Byte array of arbitrary data.
      Console.WriteLine("1) Input: A Byte array of arbitrary data.{0}", nl)
      Dim x As Integer
      For x = 0 To byteArray1.Length - 1
         byteArray1(x) = CByte(x)
         Console.Write("{0:X2} ", byteArray1(x))
         If(x + 1) Mod 20 = 0 Then
            Console.WriteLine()
         End If
      Next x
      Console.Write("{0}{0}", nl)
      
      ' 2) Convert the input Byte array to a Char array, with newlines inserted.
      charArrayLength = Convert.ToBase64CharArray( _
                                byteArray1, 0, byteArray1.Length, _
                                charArray, 0, _
                                Base64FormattingOptions.InsertLineBreaks)
      Console.WriteLine("2) Convert the input Byte array to a Char array with newlines.")
      Console.Write("   Output: A Char array (length = {0}). ", charArrayLength)
      Console.WriteLine("The elements of the array are:{0}", nl)
      Console.WriteLine(ruler)
      Console.WriteLine(New [String](charArray))
      Console.WriteLine()
      
      ' 3) Convert the Char array back to a Byte array.
      Console.WriteLine("3) Convert the Char array to an output Byte array.")
      byteArray2 = Convert.FromBase64CharArray(charArray, 0, charArrayLength)
      
      ' 4) Are the input and output Byte arrays equivalent?
      Console.WriteLine("4) The output Byte array is equal to the input Byte array: {0}", _
                            ArraysAreEqual(byteArray1, byteArray2))
   End Sub
   
   Public Shared Function ArraysAreEqual(a1() As Byte, a2() As Byte) As Boolean
      If a1.Length <> a2.Length Then
         Return False
      End If
      Dim i As Integer
      For i = 0 To a1.Length - 1
         If a1(i) <> a2(i) Then
            Return False
         End If
      Next i
      Return True
   End Function 'ArraysAreEqual
End Class