| re: Serialization of an array
Hi Elziko,
My guess is your difficulty isn't so much with serialization as it is writing to and then reading from the xml file. I can't know this for sure because your sample
doesn't show how you created your DataSet and DataTable. Here's a re working of your code that works. Hopefully, you can adapt it to solve your
problem.
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim testArray As Single() = GetTestArray()
SaveArray(testArray)
End Sub
Private Function GetTestArray() As Single()
Dim testArray(10) As Single
For i As Integer = 0 To 10
testArray(i) = 4.2
Next
Return testArray
End Function
Private Sub SaveArray(ByVal testArray() As Single)
'create memory stream and formatter
Dim msStorage As MemoryStream = New MemoryStream
Dim fStorage As IFormatter = New BinaryFormatter
Dim dsStorage As New DataSet
Dim dtStorage As New DataTable("TestTable")
With dtStorage
Dim col As New DataColumn("TestColumn", GetType(Byte()))
.Columns.Add(col)
End With
dsStorage.Tables.Add(dtStorage)
'serialise array into stream
fStorage.Serialize(msStorage, testArray)
'create byte array from stream
Dim arrB() As Byte = msStorage.ToArray()
'close stream
msStorage.Close()
Dim arrValues() As Object = {arrB}
'fill data table with byte array
dtStorage.Rows.Clear()
dtStorage.Rows.Add(arrValues)
'save to xml file
dsStorage.WriteXml("c:\depot\testArray.xml")
ReadFile()
End Sub
Private Sub ReadFile()
'read xml into data set
Dim dsStorage As New DataSet
Dim dtStorage As New DataTable("TestTable")
With dtStorage
Dim col As New DataColumn("TestColumn", GetType(Byte()))
.Columns.Add(col)
End With
dsStorage.Tables.Add(dtStorage)
dsStorage.ReadXml("c:\depot\testArray.xml")
dsStorage.Tables(0).Columns(0).DataType = GetType(Byte())
'get the bytes stored in the datatable
Dim arrBytes As Byte() = CType(dsStorage.Tables(0).Rows(0).Item(0), Byte())
'create memory stream and formatter
Dim msStorage As MemoryStream = New MemoryStream(arrBytes)
Dim fStorage As IFormatter = New BinaryFormatter
'deserialize to recreate array
msStorage.Position = 0
Dim arrOriginal() As Single = CType(fStorage.Deserialize(msStorage), Single())
'close stream
msStorage.Close()
End Sub
Craig VB.Net Team
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This reply is provided AS IS, without warranty (express or implied).
--------------------[color=blue]
>From: "elziko" <elziko@NOTSPAMMINGyahoo.co.uk>
>Subject: Serialization of an array
>Date: Wed, 7 Jul 2004 13:59:13 +0100
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>
>My intention is to store an array of singles inside a DataTable so that it
>can me peristed somehow, maybe XML file, maybe Access/SQL Server I don't
>know yet so I'm just saving it as an XML file for testing. Here are my two
>procedures for saving the array and loading it abck in again.
>
>Private Sub Save
>
> 'create memory stream and formatter
> Dim msStorage As MemoryStream = New MemoryStream
> Dim fStorage As IFormatter = New BinaryFormatter
>
> 'serialise array into stream
> fStorage.Serialize(msStorage, sngArray)
>
> 'create byte array from stream
> Dim arrB(Convert.ToInt32(msStorage.Length) - 1) As Byte
> msStorage.Seek(0, SeekOrigin.Begin)
> msStorage.Read(arrB, 0, Convert.ToInt32(msStorage.Length) - 1)
>
> 'close stream
> msStorage.Close()
>
> 'fill data table with byte array
> dtStorage.Rows.Clear()
> Dim arrValues(1) As Object
> arrValues(0) = 1
> arrValues(1) = arrB
> dtStorage.Rows.Add(arrValues)
>
> 'save to xml file
> dsStorage.WriteXml("c:\test.xml")
>
>End Sub
>
>
>Private Sub Load
>
> 'read xml into data set
> dsStorage.ReadXml("c:\test.xml")
>
> 'get the bytes stored in the datatable
> Dim arrBytes As Byte() = CType(dtStorage.Rows(0).Item(1), Byte())
>
> 'create memory stream and formatter
> Dim msStorage As MemoryStream = New MemoryStream
> Dim fStorage As IFormatter = New BinaryFormatter
>
> 'write the bytes to the stream
> msStorage.Write(arrBytes, 0, arrBytes.Length)
> msStorage.Flush()
>
> 'deserialize to recreate array
> msStorage.Position = 0
> Dim arrOriginal As Single(,) = CType(fStorage.Deserialize(msStorage),
>Single(,)) '***
>
> 'close stream
> msStorage.Close()
>
>End Sub
>
>However, when trying to reload the array, on the line commented with *** I
>get the following exception:
>
>An unhandled exception of type
>'System.Runtime.Serialization.SerializationExcept ion' occurred in
>mscorlib.dll
>
>Additional information: Binary stream does not contain a valid BinaryHeader,
>0 possible causes, invalid stream or object version change between
>serialization and deserialization.
>
>I have made sure to call flush after writing to the stream and to reset the
>position of the sream before deserialising. SO, what have I done wrong and
>there is there a much better way of doing what I'm trying to do?
>
>--
>
>Cheers,
>
>elziko
>
>
>[/color]
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