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How to convert an ADO.NET DataSet object to an ADO Recordset object in Visual Basic .NET

This article was previously published under Q316337
Caution ADO and ADO MD have not been fully tested in a Microsoft .NET Framework environment. They may cause intermittent issues, especially in service-based applications or in multithreaded applications. The techniques that are discussed in this article should only be used as a temporary measure during migration to ADO.NET. You should only use these techniques after you have conducted complete testing to make sure that there are no compatibility issues. Any issues that are caused by using ADO or ADO MD in this manner are unsupported. For more information, see the following article in the Microsoft Knowledge Base:
840667 You receive unexpected errors when using ADO and ADO MD in a .NET Framework application
This article refers to the following Microsoft .NET Framework Class Library namespaces:
  • System.Data
  • System.Data.SqlClient


This step-by-step article describes how to convert an ADO.NET DataSet object to an ActiveX Data Objects (ADO) Recordset object.

This article uses the XML approach to convert the DataSet to an ADO Recordset. The XML format that is persisted in ADO differs from the XML format of the DataSet. Therefore, you can simplify the conversion process if you convert from one XML format to the other. The ADO Persist provider facilitates to load the .xml file to an ADO Recordset, as long as it is in the ADO XML format.

Note When you use this method, you can only create a read-only ADODB Recordset. To create an updatable Recordset, create an empty connected Recordset, and then insert all the rows.


The following list outlines the recommended hardware, software, network infrastructure, and service packs that are required:
  • Microsoft Windows XP, Windows 2000, or Windows NT 4.0 Service Pack 6a
  • Microsoft Data Access Components (MDAC) 2.6 or later
  • Microsoft Visual Studio .NET
This article assumes that you are familiar with the following topics:
  • Microsoft Visual Basic .NET syntax
  • ADO.NET and earlier versions of ADO
  • DataSet and ADO Recordset XML formats

Create an XSLT File

  1. In Notepad, copy and then paste the following XSLT code:
    <?xml version="1.0"?> <xsl:stylesheet xmlns:xsl="" version="1.0"xmlns:rs="urn:schemas-microsoft-com:rowset"xmlns:z="#RowsetSchema"><xsl:output method="xml" indent="yes"/><xsl:param name="tablename"/><xsl:template match="NewDataSet"><rs:data>	<xsl:for-each select="./node()[local-name(.)=$tablename]">		<z:row>			<xsl:for-each select="@*">				<xsl:copy-of select="."/>			</xsl:for-each>		</z:row>	</xsl:for-each></rs:data></xsl:template></xsl:stylesheet>					
  2. Save the file as Test.xsl.

Create a Visual Basic .NET DLL

  1. Start Visual Studio .NET.
  2. On the File menu, point to New, and then click Project.
  3. Click Visual Basic Projects under Project Types, and then click Class Library under Templates.
  4. Type ConvertDStoRS in the Name: box, and then click OK.
  5. In Class1.vb, replace existing code with following code:
    Imports System.DataImports System.XmlImports System.Xml.XPathImports System.Xml.XslImports System.IO'**************************************************************************'   Class Name  : ConvertToRs'   Description : This class converts a DataSet to a ADODB Recordset.'**************************************************************************Public Class ConvertToRs  '**************************************************************************  '   Method Name : GetADORS  '   Description : Takes a DataSet and converts into a Recordset. The converted   '                 ADODB recordset is saved as an XML file. The data is saved   '                 to the file path passed as parameter.  '   Output      : The output of this method is long. Returns 1 if successfull.   '                 If not throws an exception.   '   Input parameters:  '               1. DataSet object  '               2. Database Name  '               3. Output file - where the converted should be written.  '**************************************************************************  Public Function GetADORS(ByVal ds As DataSet, ByVal dbname As String, ByVal xslfile As String, _    ByVal outputfile As String) As Long    'Create an xmlwriter object, to write the ADO Recordset Format XML    Try      Dim xwriter As New XmlTextWriter(outputfile, System.Text.Encoding.Default)      'call this Sub to write the ADONamespaces to the XMLTextWriter      WriteADONamespaces(xwriter)      'call this Sub to write the ADO Recordset Schema      WriteSchemaElement(ds, dbname, xwriter)      Dim TransformedDatastrm As New MemoryStream      'Call this Function to transform the Dataset xml to ADO Recordset XML      TransformedDatastrm = TransformData(ds, xslfile)      'Pass the Transformed ADO REcordset XML to this Sub      'to write in correct format.      HackADOXML(xwriter, TransformedDatastrm)      xwriter.Flush()      xwriter.Close()      'returns 1 if success      Return 1    Catch ex As Exception      'Returns error message to the calling function.      Err.Raise(100, ex.Source, ex.ToString)    End Try  End Function  Private Sub WriteADONamespaces(ByRef writer As XmlTextWriter)    'The following is to specify the encoding of the xml file    'writer.WriteProcessingInstruction("xml", "version='1.0' encoding='ISO-8859-1'")    'The following is the ado recordset format    '<xml xmlns:s='uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882'     '        xmlns:dt='uuid:C2F41010-65B3-11d1-A29F-00AA00C14882'    '        xmlns:rs='urn:schemas-microsoft-com:rowset'     '        xmlns:z='#RowsetSchema'>    '    </xml>    'Write the root element    writer.WriteStartElement("", "xml", "")    'Append the ADO Recordset namespaces    writer.WriteAttributeString("xmlns", "s", Nothing, "uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882")    writer.WriteAttributeString("xmlns", "dt", Nothing, "uuid:C2F41010-65B3-11d1-A29F-00AA00C14882")    writer.WriteAttributeString("xmlns", "rs", Nothing, "urn:schemas-microsoft-com:rowset")    writer.WriteAttributeString("xmlns", "z", Nothing, "#RowsetSchema")    writer.Flush()  End Sub  Private Sub WriteSchemaElement(ByVal ds As DataSet, ByVal dbname As String, ByRef writer As XmlTextWriter)    'ADO Recordset format for defining the schema    ' <s:Schema id='RowsetSchema'>    '            <s:ElementType name='row' content='eltOnly' rs:updatable='true'>    '            </s:ElementType>    '        </s:Schema>    'write element schema    writer.WriteStartElement("s", "Schema", "uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882")    writer.WriteAttributeString("id", "RowsetSchema")    'write element ElementTyoe    writer.WriteStartElement("s", "ElementType", "uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882")    'write the attributes for ElementType    writer.WriteAttributeString("name", "", "row")    writer.WriteAttributeString("content", "", "eltOnly")    writer.WriteAttributeString("rs", "updatable", "urn:schemas-microsoft-com:rowset", "true")    WriteSchema(ds, dbname, writer)    'write the end element for ElementType    writer.WriteFullEndElement()    'write the end element for Schema     writer.WriteFullEndElement()    writer.Flush()  End Sub  Private Sub WriteSchema(ByVal ds As DataSet, ByVal dbname As String, ByRef writer As XmlTextWriter)    Dim i As Int32 = 1    Dim dc As DataColumn    For Each dc In ds.Tables(0).Columns      dc.ColumnMapping = MappingType.Attribute      writer.WriteStartElement("s", "AttributeType", "uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882")      'write all the attributes       writer.WriteAttributeString("name", "", dc.ToString)      writer.WriteAttributeString("rs", "number", "urn:schemas-microsoft-com:rowset", i.ToString)      writer.WriteAttributeString("rs", "baseCatalog", "urn:schemas-microsoft-com:rowset", dbname)      writer.WriteAttributeString("rs", "baseTable", "urn:schemas-microsoft-com:rowset", _            dc.Table.TableName.ToString)      writer.WriteAttributeString("rs", "keycolumn", "urn:schemas-microsoft-com:rowset", _            dc.Unique.ToString)      writer.WriteAttributeString("rs", "autoincrement", "urn:schemas-microsoft-com:rowset", _            dc.AutoIncrement.ToString)      'write child element      writer.WriteStartElement("s", "datatype", "uuid:BDC6E3F0-6DA3-11d1-A2A3-00AA00C14882")      'write attributes      writer.WriteAttributeString("dt", "type", "uuid:C2F41010-65B3-11d1-A29F-00AA00C14882", _            GetDatatype(dc.DataType.ToString))      writer.WriteAttributeString("dt", "maxlength", "uuid:C2F41010-65B3-11d1-A29F-00AA00C14882", _            dc.MaxLength.ToString)      writer.WriteAttributeString("rs", "maybenull", "urn:schemas-microsoft-com:rowset", _            dc.AllowDBNull.ToString)      'write end element for datatype      writer.WriteEndElement()      'end element for AttributeType      writer.WriteEndElement()      writer.Flush()      i = i + 1    Next    dc = Nothing  End Sub  'Function to get the ADO compatible datatype  Private Function GetDatatype(ByVal dtype As String) As String    Select Case (dtype)      Case "System.Int32"        Return "int"      Case "System.DateTime"        Return "dateTime"    End Select  End Function  'Transform the data set format to ADO Recordset format  'This only transforms the data  Private Function TransformData(ByVal ds As DataSet, ByVal xslfile As String) As MemoryStream    Dim instream As New MemoryStream    Dim outstream As New MemoryStream    'write the xml into a memorystream    ds.WriteXml(instream, XmlWriteMode.IgnoreSchema)    instream.Position = 0    'load the xsl document    Dim xslt As New XslTransform    xslt.Load(xslfile)    'create the xmltextreader using the memory stream    Dim xmltr As New XmlTextReader(instream)    'create the xpathdoc    Dim xpathdoc As XPathDocument = New XPathDocument(xmltr)    'create XpathNavigator    Dim nav As XPathNavigator    nav = xpathdoc.CreateNavigator    'Create the XsltArgumentList.    Dim xslArg As XsltArgumentList = New XsltArgumentList    'Create a parameter that represents the current date and time.    Dim tablename As String    xslArg.AddParam("tablename", "", ds.Tables(0).TableName)    'transform the xml to a memory stream    xslt.Transform(nav, xslArg, outstream)    instream = Nothing    xslt = Nothing    '        xmltr = Nothing    xpathdoc = Nothing    nav = Nothing    Return outstream  End Function  '**************************************************************************  '   Method Name : ConvertToRs  '   Description : The XSLT does not tranform with fullendelements. For example,   '               <root attr=""/> intead of <root attr=""><root/>. ADO Recordset   '               cannot read this. This method is used to convert the   '               elements to have fullendelements.  '**************************************************************************  Private Sub HackADOXML(ByRef wrt As XmlTextWriter, ByVal ADOXmlStream As System.IO.MemoryStream)    ADOXmlStream.Position = 0    Dim rdr As New XmlTextReader(ADOXmlStream)    Dim outStream As New MemoryStream    'Dim wrt As New XmlTextWriter(outStream, System.Text.Encoding.Default)    rdr.MoveToContent()    'if the ReadState is not EndofFile, read the XmlTextReader for nodes.    Do While rdr.ReadState <> ReadState.EndOfFile      If rdr.Name = "s:Schema" Then        wrt.WriteNode(rdr, False)        wrt.Flush()      ElseIf rdr.Name = "z:row" And rdr.NodeType = XmlNodeType.Element Then        wrt.WriteStartElement("z", "row", "#RowsetSchema")        rdr.MoveToFirstAttribute()        wrt.WriteAttributes(rdr, False)        wrt.Flush()      ElseIf rdr.Name = "z:row" And rdr.NodeType = XmlNodeType.EndElement Then        'The following is the key statement that closes the z:row         'element without generating a full end element        wrt.WriteEndElement()        wrt.Flush()      ElseIf rdr.Name = "rs:data" And rdr.NodeType = XmlNodeType.Element Then        wrt.WriteStartElement("rs", "data", "urn:schemas-microsoft-com:rowset")      ElseIf rdr.Name = "rs:data" And rdr.NodeType = XmlNodeType.EndElement Then        wrt.WriteEndElement()        wrt.Flush()      End If      rdr.Read()    Loop    wrt.WriteEndElement()    wrt.Flush()  End SubEnd Class
  6. On the Build menu, click Build Solution. The ConvertDStoRS.dll Visual Basic .NET DLL is created.

Create a Visual Basic .NET Project

  1. To create a new Visual Basic .NET console application, follow these steps:
    1. Start Visual Studio .NET.
    2. On the File menu, point to New, and then click Project.
    3. Click Visual Basic Projects under Project Types, and then click Console Application under Templates.
  2. To add references to ConvertDStoRS.dll and the ActiveX Data Objects (ADO) Library, follow these steps:
    1. On the Project menu, click Add Reference.
    2. In the Add Reference dialog box, on the .NET tab, click Browse, and then locate the ConvertDStoRS.dll file that you created in Step 6 of the Create a Visual Basic .NET DLL subsection of this article.
    3. Click ConvertDStoRS.dll, click Select, and then click OK.
    4. In the Add Reference dialog box, click the COM tab.
    5. Click Microsoft ActiveX Data Objects Library 2.6 (or a later version) in the Component Name list, click Select, and then click OK.
  3. In Module1.vb, replace the existing code with following code:
    Imports System.DataImports System.Data.SqlClientModule Module1    Sub Main()        Dim cnNwind As New SqlConnection("data source=mySQLServer;Integrated Security=SSPI;initial catalog=pubs;")        Dim daAuthors As New SqlDataAdapter("Select * from Authors", cnNwind)        Dim ds As New DataSet()        Try            daAuthors.Fill(ds, "Authors")            daAuthors.FillSchema(ds.Tables("Authors"), SchemaType.Source)            Dim objconvert As New ConvertDStoRS.ConvertToRs()            Dim result As Long            result = objconvert.GetADORS(ds, "Northwind", "c:\temp\test.xsl", "c:\temp\result.xml")            If result = 1 Then                Dim rs As New ADODB.Recordset()                rs.Open("c:\temp\result.xml")                Console.WriteLine("RecordCount =" & str(rs.RecordCount))                Console.Read()            End If        Catch sqlex As SqlException            Console.WriteLine(sqlex.Message)        Catch ex As Exception            Console.WriteLine(ex.Message)        End Try           End SubEnd Module					
  4. Build and then run the project. Notice that the record count is displayed in the Console window.
Note To handle special characters in the data, write the processing instruction with the encoding attribute. You can make this change in the ConvertToRs class that is mentioned in the class1.vb file of the "Create a Visual Basic .NET DLL" section of this article or in the result.xml file. Note that the processing instruction only informs the encoding format to the parser, and the data must be in the specified encoding format. For example:
<?xml version="1.0" encoding="ISO-8859-1"?><?xml version="1.0" encoding="UTF-8"?> 
You can control the encoding of the data in .NET several ways. For example: XmlTextWriter constructor can be used.
Public Sub New(Stream, Encoding)
For additional information, click the article numbers below to view the articles in the Microsoft Knowledge Base:
308064 How To Persist an ADO.NET DataSet as XML by Using Visual Basic .NET
301216 How To Populate a DataSet Object from a Database by Using Visual Basic .NET
313590 INFO: Roadmap for ADO.NET
313649 INFO: Roadmap for XML Integration with ADO.NET

Article ID: 316337 - Last Review: 11/28/2007 18:04:23 - Revision: 7.1

Microsoft ADO.NET 1.1, Microsoft ADO.NET 1.0, Microsoft Visual Basic .NET 2003 Standard Edition, Microsoft Visual Basic .NET 2002 Standard Edition

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