Two Encoding decode...

[Xmas79]

Let's suppose a string. I use

dim abyte() as byte
abyte=encoding.unicode.getbytes(mystr)

and it encode it. Now, if I encode again into another array, I get the char array i would get if I translate directly the string to char array. Fun or am I wrong ??

[Tygur]

What do you mean by "encode again into another array"? To get the characters back, you have to decode them, not encode them again.

Using encoding.unicode.getchars will get the characters:

Dim mychars() As Char = Encoding.Unicode.GetChars(abyte)

[Xmas79]

Sure I have to decode it! The problem was when I tried to convert it to a String and again to bytes... I got a bad rapresentation. Don't know why, but I got 2 different arrays...

[Tygur]

Can you post the code you used to do this?

[Xmas79]

Look at this thread for understanding the problem I had.
http://www.vbforums.com/showthread.p...hreadid=244481

Public Function DataSetToString(ByRef ds As DataSet) As String
        Dim ms As MemoryStream = New MemoryStream()
        Dim bf As New BinaryFormatter()
 
        bf.Serialize(ms, ds)
        ms.Position = 0
 
        Dim sr As Byte()
        sr = ms.ToArray()
 
        Return Encoding.ASCII.GetString(sr) 'or unicode, is the same
    End Function
 
    Public Function StringToDataSet(ByVal data As String) As DataSet
        Dim ms As New IO.MemoryStream()
        Dim sw As New IO.StreamWriter(ms)
        Dim bf As New BinaryFormatter()
 
        sw.Write(data)
        sw.Flush()
        ms.Position = 0
 
        Dim ds As New DataSet()
        ms.Position = 0
        ds = bf.Deserialize(ms)
 
        Return ds
    End Function

Those are the functions I used to serialize and deserialize the DataSet. One in the server, the other in the client. The two Encoding are: one in these functions, the other when I send the string through the network.
Finally I found the problem: the last line of the DataSetToString function returned a wrong converted string!!! Infact looking at the byte array of the serialization and the byte array of the deserialization there were a lot of differences!
The original topic wasn't pointed at this, I know, but with this operation it seemed to me that I could get only one "encoding" of the string and not two.

[Tygur]

I've done this in Java, and then in VB.NET. To avoid problems like this, I would put the hex representation of the bytes in the string instead of what you're doing. While it does effectively double the amount of space the object takes up while in transit, it prevents unusual characters from being present in the string.

As for your code, if you're going to encode the string in ASCII, you should also decode it in ASCII. I would change this line:
Dim sw As New IO.StreamWriter(ms)

...to this one:
Dim sw As New IO.StreamWriter(ms, Encoding.ASCII)

The problem, like I said, is that you could get unusual/unexpected characters, such as null characters, for example.

Here is the code that I used to encode/decode the byte array to/from a string. At the time, I just wrote it real qucik, so it's possible that it could be more efficiently coded.

'Conversion to/from hex string
    Private Shared Function ByteArrayToHexString(ByVal ByteArray() As Byte) As String
        Dim B As Byte
        Dim sHex As String
        Dim StrOut As New System.Text.StringBuilder()
        For Each B In ByteArray
            sHex = Hex(B)
            If sHex.Length = 1 Then
                sHex = "0" & sHex
            End If
            StrOut.Append(sHex)
        Next
        Return StrOut.ToString
    End Function
    Private Shared Function HexStringToByteArray(ByVal Str As String) As Byte()
        Dim Bytes As New System.Collections.ArrayList()
        Dim B As Byte
        Dim I As Integer
        For I = 0 To Str.Length - 1 Step 2
            Bytes.Add(CType(CInt("&H" & Str.Substring(I, 2)), Byte))
        Next
        Return Bytes.ToArray(B.GetType)
    End Function

[Xmas79]

I was wandering if I really need to translate the dataset to a string... Because I'm using sockets to implement network functionality, i saw that socket.send method needs a byte array... and serialization just does this... I didn't try yet, I'll do it now. I'll let you know.

Thx Tygur.