By Sean Rhone

After being assigned a project at work and becoming extreamly frustrated with the examples I found, I decided to create this tutorial using C# to transform a xml file into a another xml file using XslTransform.

The code below use XSLT to transform an in-house data xml file into a xml file using a clients XSLT specification. This tutorial shows examples of XSLT, extending XSLT with C#, XSLT variables, and Start by creating a standard Console application with the code below. Create the XML and XSLT below and put in the application\bin\debug folder. After running this application in the same folder you should have a Client.xml.

The code is well commented so I will not go on about how things work.

   w.WriteStartDocument();
   
   //This creates the link between the xml file and the validation xslt file
   //w.WriteDocType("ImportActionCodes",null,"ImportActionCodes.dtd",null);

   //Do the work
   xslTrans.Transform(xPath,xsltArg,w);
   
   //Close the file
   w.Close();
  }
 }
 public class CustomDate
 {
  //Custom class for creating/getting data

  string currentFile = "";
  public CustomDate(string xmlFile)
  {
   //during instan we pass the current xml file we are working on
   currentFile = xmlFile;
  }
  public string GetDate()
  {
   //Create formatted date for Header/SentDate
   System.DateTime dt = System.DateTime.Now;
   string sdt =  dt.ToString("yyyy-MM-dd");
   return sdt;
  }
  public string GetTime()
  {
   //Create formatted time for Header/SentTime
   System.DateTime dt = System.DateTime.Now;
   string sdt =  dt.ToString("HH-mm-ss");
   return sdt;
  }
  public string GetValue(string xPath)
  {
   XmlDocument doc = new XmlDocument();
   doc.Load(currentFile);
   XmlNode aNode  = doc.SelectSingleNode(xPath);
   string retVal = aNode.InnerText;
   
   return retVal;
  }
  public string ConvertDate(string cValue)
  {
   //Does nothing of real value except showing that you can pass data from the xslt into c#
   string retVal = cValue;
   return retVal;
  }
 }
}

Now here is the XML file used for the conversion, save as in-House.xml in 
the \bin\debug folder along with the XSLT file.

<?xml version="1.0" encoding="UTF-8"?>
<ACTION_INFORMATION>
    <ACTION>
        <LOAN_NUM>123456789</LOAN_NUM>
        <SERVICER_ID>GreatClient</SERVICER_ID>
        <CASE_ID>ABCD_1234</CASE_ID>
        <MILESTONE_INFORMATION>
            <MS>
                <MS_NAME>File Received</MS_NAME>
                <MS_SCHEDULED_DATE>2002-02-27T-00-00</MS_SCHEDULED_DATE>
                <MS_SEQ>1</MS_SEQ>
            </MS>
            <MS>
                <MS_NAME>BK Case Filed (Generic)</MS_NAME>
                <MS_SCHEDULED_DATE>2002-02-19T-00-00</MS_SCHEDULED_DATE>
                <MS_SEQ>2</MS_SEQ>
            </MS>
            <MS>
                <MS_NAME>Figures Requested</MS_NAME>
                <MS_SCHEDULED_DATE>2004-10-07T-00-00</MS_SCHEDULED_DATE>
                <MS_SEQ>3</MS_SEQ>
            </MS>
        </MILESTONE_INFORMATION>
    </ACTION>
</ACTION_INFORMATION>

Here is the XSLT file used for transformation, save as Action.xsl

<!--XSLT Tutorial / Programmer: Sean Rhone / Created: 10/21/2004 -->

<!--this xmlns is standard and should be in all This defines our custom namespace -->

<xsl:stylesheet xmlns:xsl="http://www.w3.org/1999/XSL/Transform" 
version="1.0" xmlns:sDate="urn:sentDate">

<!-- The template match="/" means match every / found in a xml file-->
  <xsl:template match="/">
 <!-- This is a hard coded element to create as is the <Header></Header>-->
 <ImportActionCodes>
  <Header>
   <BusinessPartnerID>123456789</BusinessPartnerID>

   <!-- Notice select="sDate:GetDate() and GetTime()-->
   <!-- This calles the GetDate/GetTime methods in the C# code-->
   <SentDate><xsl:value-of select="sDate:GetDate()"/></SentDate>

   <SentTime><xsl:value-of select="sDate:GetTime()"/></SentTime>
   <FromWebMail>Somebody@YourISP.com</FromWebMail>
   <TransactionCount>2</TransactionCount>
  </Header>


  <!-- As any programming language there are variables-->
  <!-- This call creates a variable named "LoanNum" which can be used globaly-->
  <xsl:variable name="LoanNum" select="ACTION_INFORMATION/ACTION/LOAN_NUM" />
 
  <!-- I want to handle repeating sections of the xml -->  
  <xsl:for-each select="ACTION_INFORMATION/ACTION/MILESTONE_INFORMATION/MS">

   <!-- if the current element name equals then we do some work-->
   <xsl:if test="MS_NAME='File Received'">
    
    <!-- Test string for lenght string-lenght is actually a XPath function-->
    <xsl:if test="string-length(MS_SCHEDULED_DATE)>0">
     <AOD>
      <!--Create a <Account> element and populate with the LoanNum variable-->
      <!-- NOTE you must use a $ before the variable-->
      <Account><xsl:value-of select="$LoanNum"/></Account>
    
      <!--substring() is another XPath function but the idea here is -->
      <!--to show passing a value back to C# for some sort of processing -->
      <Date><xsl:value-of select="sDate:ConvertDate(substring(MS_SCHEDULED_DATE,1,10))"/></Date>
     </AOD>
    </xsl:if>
   </xsl:if>
   <xsl:if test="MS_NAME='BK Case Filed (Generic)'">
    <xsl:if test="string-length(MS_SCHEDULED_DATE)>0">
     <CFD>
      <Account><xsl:value-of select="$LoanNum"/></Account>
      <Date><xsl:value-of select="sDate:ConvertDate(substring(MS_SCHEDULED_DATE,1,10))"/></Date>

      <!--This call show how to apply some rules to a select elemets -->
      <!--If this were a html out you could change font/color etc -->
      <!--Here I just show you how to call and create a new element, the important -->
      <!--thing to know is the <xsl:template match="MS_SEQ"> matches the current element name -->
      <xsl:apply-templates select="MS_SEQ" />
     </CFD>
    </xsl:if>
   </xsl:if>
   <xsl:if test="MILESTONE_NAME='Figures Requested'">
    <xsl:if test="string-length(MS_SCHEDULED_DATE)>0">
     <COTD>
      <Account><xsl:value-of select="$LoanNum"/></Account>
      <Date><xsl:value-of select="sDate:ConvertDate(substring(MS_SCHEDULED_DATE,1,10))"/></Date>
     </COTD>
    </xsl:if>
   </xsl:if>
   
  </xsl:for-each>
 </ImportActionCodes>
  </xsl:template>
<xsl:template match="MS_SEQ">
 <MILE_SEQ>
  <xsl:value-of select="." />
 </MILE_SEQ>
</xsl:template>
</xsl:stylesheet>