HOW TO: Format DateTime and Date Values in the XML Extracted from an ADO.NET DataSet by Using Visual Basic .NET (811767)

SUMMARY

This step-by-step article describes how to format DateTime and Date values in the XML that is extracted from an ADO.NET DataSet object. In ADO.NET, the DateTime and Date values of DataTable columns are written in the XSD DateTime and Date formats when the DataSet is saved as XML. The standard XSD DateTime and Date formats are CCYY-MM-DDThh:mm:ss and CCYY-MM-DD, respectively, because the underlying XSD schema of the DataSet maps the DateTime and Date columns of the database to the DateTime and XSD Date data types.

To generate XML where DateTime and Date values are represented in the required custom formats, use either of the following methods:

• Use the XmlConvert class.
• Apply an XSLT transformation (XSLT) on the XML representation of DataSet data.

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Use XmlConvert Class

1. Open Microsoft Visual Studio .NET. In Visual Basic .NET, create a new ASP.NET Web Application project that is named DateTimeXmlConvert.
2. Right-click the designer surface of WebForm1.aspx, and then click View Code.
3. Add the following code to the end of Imports directives section in WebForm1.aspx.vb:

   	Imports System.Xml
   	Imports System.Text
   	Imports System.Data.SqlClient

4. Paste the following code in the Page_Load event:

   	
   	' Change SqlServerName, UserId and Password in the following connection string.
   	Dim conn As String =  "Server=<SQLServerName>; database=Northwind; user id=<UserID>; password=<Password>;" 
   	Dim connection As SqlConnection =  New SqlConnection() 
   	connection.ConnectionString = conn
    
   	Dim objDataSet As DataSet =  New DataSet() 
   	Dim objAdapter As SqlDataAdapter =  New SqlDataAdapter() 
   	Dim objCmd As SqlCommand =  New SqlCommand() 
    
   	' Retrieve the first 10 records from the employees table.
   	objCmd.CommandText = "select top 10 FirstName,BirthDate from employees"
   	objCmd.Connection = connection
   	objAdapter.SelectCommand = objCmd
   	objAdapter.Fill(objDataSet)
    
   	connection.Close()
    
   	' Create an instance of XmlTextReader class that reads the XML data.
   	Dim xmlReader As XmlTextReader =  New XmlTextReader(objDataSet.GetXml(),XmlNodeType.Element,Nothing) 
    
   	Response.ContentType = "text/xml"
   	Dim xmlWriter As XmlTextWriter =  New XmlTextWriter(Response.OutputStream,Encoding.UTF8) 
   	xmlWriter.Indentation = 4
   	xmlWriter.WriteStartDocument()
   	Dim elementName As String =  "" 
    
   	' Parse & display each node
   	While xmlReader.Read()
   		Select Case xmlReader.NodeType
   			Case XmlNodeType.Element
   				xmlWriter.WriteStartElement(xmlReader.Name)
   				elementName = xmlReader.Name
   
   			Case XmlNodeType.Text
   				If elementName.ToLower() = "birthdate" Then
   					xmlWriter.WriteString(XmlConvert.ToDateTime(xmlReader.Value).ToString())
   				Else 
   					xmlWriter.WriteString(xmlReader.Value)
   				End If
   
   			Case XmlNodeType.EndElement
   				xmlWriter.WriteEndElement()
   
   		End Select
   	End While
   	xmlWriter.Close()
   

5. Save the changes to WebForm1.aspx.vb.
6. On the Build menu, click Build Solution.
7. Start Microsoft Internet Explorer and open WebForm1.aspx by specifying the following URL, where IISServerName is the name of your Microsoft Internet Information Services (IIS) server:

   http://IISServerName/DateTimeXmlConvert/WebForm1.aspx

You can now see that the XML file that is rendered in the browser is displayed in custom DateTime format.

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Apply an XSLT Transformation on the XML Representation of DataSet Data

You can use inline script blocks and external code components, known as XSLT Extension objects, to implement custom routines. These are invoked during an XSLT to perform calculations and process data. Microsoft recommends that you avoid using inline script blocks. You can use extension objects to implement custom routines when you design portable XSLT style sheets.

Create an ASP.NET Web Form

1. Create a new Visual Basic .NET ASP.NET Web Application project that is named DateTimeXSLT.
2. Add a new class that is named DateConvertor.vb to the project.
3. Replace the existing code with the following code in the DateConvertor.vb class:

   Public Class DateConvertor
    Public Function GetDateTime(ByVal data As String, ByVal format As String) As String
     Dim dt As DateTime = DateTime.Parse(data)
     Return dt.ToString(format)
    End Function
   End Class
   

4. Save the changes to DateConvertor.vb.
5. Right-click the designer surface of WebForm1.aspx, and then click View Code.
6. Add the following code to the end of Imports directives section in WebForm1.aspx.vb:

   	Imports System.IO
   	Imports System.Xml
   	Imports System.Xml.Xsl
   	Imports System.Xml.XPath
   	Imports System.Data.SqlClient

7. Paste the following code in the Page_Load event:

   	' Change SqlServerName, UserId and Password in the following connection string.
   	Dim strConn As String =  "Server=<SQLServerName>; database=Northwind; user id=<UserID>; password=<Password>;" 
   	Dim connection As SqlConnection =  New SqlConnection() 
   	connection.ConnectionString = strConn
    
   	Dim objDataSet As DataSet =  New DataSet() 
   	Dim objAdapter As SqlDataAdapter =  New SqlDataAdapter() 
   	Dim objCmd As SqlCommand =  New SqlCommand() 
   	' Retrieve all records from employees table.
   	objCmd.CommandText = "select FirstName,BirthDate from employees"
   	objCmd.Connection = connection
   	objAdapter.SelectCommand = objCmd
   	objAdapter.Fill(objDataSet)
    
   	connection.Close()
    
   	' Create an instance of StringReader class that reads the XML data.
   	Dim reader As StringReader =  New StringReader(objDataSet.GetXml()) 
   	Dim doc As XPathDocument =  New XPathDocument(reader) 
    
   	' Create an XslTransform object and load xslt file.
   	Dim transform As XslTransform =  New XslTransform() 
   	transform.Load(Me.MapPath("DateTime.xslt"))
    
   	'Add an object to convert  DateTime format.
   	Dim objDateConvertor As DateConvertor =  New DateConvertor() 
   	Dim args As XsltArgumentList =  New XsltArgumentList() 
   	args.AddExtensionObject("urn:ms-kb", objDateConvertor)
    
   	transform.Transform(doc, args, Response.OutputStream)
   	

8. Save the changes to WebForm1.aspx.vb.

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Create a Sample XSLT Document

1. Add a new XSLT file that is named DateTime.xslt to the DateTimeXSLT ASP.NET Web Project.
2. Replace the generated code with the following code. (Use notepad as an intermediary tool if you experience any encoding or character problems when you try to paste the following code.)

   <?xml version='1.0'?>
   <xsl:stylesheet version="1.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"  xmlns:myObj="urn:ms-kb">
   
   <xsl:template match="NewDataSet">
   <table><xsl:attribute name="border">1</xsl:attribute>
      <TR><TD>Employee name</TD><TD>Original DateTime Format</TD><TD>Changed DateTime Format</TD></TR>
   	<xsl:apply-templates select="*"/>
   </table>
   </xsl:template>
   
   <xsl:template match="*">
   	<TR>
   	<xsl:apply-templates select="*"/>
   	</TR>
   </xsl:template>
   
   <xsl:template match="FirstName">
   <TD>
   	<xsl:value-of select="."/>
   </TD>
   </xsl:template>
   
   <xsl:template match="BirthDate">
   <xsl:variable name="Date" select="."/>
   <TD><xsl:value-of select="$Date"/></TD>
   <TD>	
   	<xsl:value-of select="myObj:GetDateTime($Date, 'F')"/>
   </TD>
   </xsl:template>
   
   </xsl:stylesheet>
   

3. Save the changes to DateTime.xslt.

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Testthe XSLT Transformation by Using the ASP.NET Web Form

1. Save the changes to the DateTimeXSLT ASP.NET Web Project.
2. On the Build menu, click Build Solution.
3. Start Microsoft Internet Explorer and open WebForm1.aspx by specifying the following URL, where IISServerName is the name of your Microsoft Internet Information Services (IIS) server:

   				http://IISServerName/DateTimeXSLT/WebForm1.aspx

You can now see that two DateTime formats, the DateTime format of DataSet and the transformed DateTime format on the WebForm1.aspx page.

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