C# XSLT: How to debug this error ?

Question

I have to include a C# script in my XSLT file .. So as to calculate the difference between two dateTime values(and add it to some other values) .. I need to accept all the possible formats of date .. I was suppose to do it with XSLT .. but as XSLT doesn't allow to do it (implicitely) .. I found this remedy of calling a C# script .. I have to call that XSL transformation from many different C# programs .. so It would be painful (rather impossible) to write this code in all calling C# code .. :( Can you find some remedy for this

This is the XSLT code ..

 <xsl:variable name="date1" select="//date1"/>
  <xsl:variable name="date2" select="//date2"/>
  <msxsl:script language="C#" implements-prefix="cs">
    <![CDATA[

    private static string[] formats = new string[]
    {
        "MM/dd/yyyy HH:mm:ss tt",
        "MM/dd/yyyy HH:mm:ss",
        "MM/dd/yyyy H:mm:ss tt",
        "MM/dd/yyyy H:mm:ss",
"M/dd/yyyy HH:mm:ss tt",
"M/dd/yyyy HH:mm:ss",
"M/dd/yyyy H:mm:ss tt",
"M/dd/yyyy H:mm:ss",
"MM/d/yyyy HH:mm:ss tt",
"MM/d/yyyy HH:mm:ss",
"MM/d/yyyy H:mm:ss tt",
"MM/d/yyyy H:mm:ss", 
"M/d/yyyy HH:mm:ss tt",   
"M/d/yyyy HH:mm:ss", 
"M/d/yyyy H:mm:ss tt", 
"M/d/yyyy H:mm:ss",      
    };


      public string datedif(string date1, string date2) {


            DateTime startTime;
            DateTime endTime;
            DateTime ThirdDate;

string date3="12/12/2009 00:00:00";

            DateTime.TryParseExact(date1, formats, new CultureInfo("en-US"), 
                                   DateTimeStyles.None, out startTime);
            DateTime.TryParseExact(date2, formats, new CultureInfo("en-US"), 
                                   DateTimeStyles.None, out endTime);
            DateTime.TryParseExact(date3, formats, new CultureInfo("en-US"), 
                                   DateTimeStyles.None, out ThirdDate);

ThirdDate = ThirdDate.Add(endTime.Subtract(startTime));


string result = ThirdDate.ToString("MM'/'dd'/'yyyy' 'HH':'mm':'ss");
return(result);

         }
     ]]>
  </msxsl:script>
  <xsl:template match="datediff">
    <xsl:element name="{local-name()}">
      <xsl:value-of select="cs:datedif($date1, $date2)" />
    </xsl:element>
  </xsl:template>

and the errors are :

1. The name 'DateTimeStyles' does not exist in the current context

2. The type or namespace name 'CultureInfo' could not be found (are you missing a using directive or an assembly reference?)

ThanQ very much .. Jon Skeet

Answer 1

Those are errors from the C# compiler. You need to give a lot more information on what you're trying to do.

It sounds like you're at least missing a using directive of:

using System.Globalization;

but you haven't said where the errors are or what you're doing.

EDIT: If you can't change anything else, then change the references to DateTimeStyles and CultureInfo to be fully qualified:

global::System.Globalization.DateTimeStyles
global::System.Globalization.CultureInfo

So for example you'd have:

DateTime.TryParseExact(date1, formats,
     new global::System.Globalization.CultureInfo("en-US"), 
     global::System.Globalization.DateTimeStyles.None, out startTime);

Answer 2

The bug is on this line:

DateTime.TryParseExact(date1, formats, new CultureInfo("en-US"), DateTimeStyles.None, out startTime);

Did you reference the System.Globalization namespace?

As @JonSkeet suggested, a workaround is to update your references like so:

global::System.Globalization.DateTimeStyles
global::System.Globalization.CultureInfo

Answer 3

It is often easier to move scripts into extension-objects; you do this by exposing a regular method on a basic object, and using XsltArgumentList to expose it in an xslt namespace:

XsltArgumentList args = new XsltArgumentList();
args.AddExtensionObject("my-namespace", obj);

In your xslt, you associate your namespace-alias with the namespace, and just use "alias:someFunc(...)" in the xslt. This gives you better IDE support (but you can't just use xslt); example:

using System;
using System.Globalization;
using System.IO;
using System.Xml.XPath;
using System.Xml.Xsl;
public class MyExtensionObject
{
    private static string[] formats = new string[] { /* ... */ };
    public string dateDiff(string x, string y)
    {
        CultureInfo culture = new CultureInfo("en-US");
        TimeSpan delta = DateTime.ParseExact(y, formats, culture, DateTimeStyles.None)
            - DateTime.ParseExact(x, formats, culture, DateTimeStyles.None);
        return delta.ToString();
    }
}
class Program
{
    static void Main()
    {
        XsltArgumentList args = new XsltArgumentList();
        args.AddExtensionObject("my-namespace", new MyExtensionObject());
        XslTransform xslt = new XslTransform();
        xslt.Load("foo.xslt");
        using(TextWriter output = File.CreateText("out.txt")) {
            XPathDocument input = new XPathDocument("foo.xml");
            xslt.Transform(input, args, output);
        }

    }
}

xslt:

<?xml version="1.0" encoding="utf-8"?>
<xsl:stylesheet version="1.0"
    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
    xmlns:bar="my-namespace" >
    <xsl:template match="xml">
      <result value="{bar:dateDiff(date1,date2)}"/>
    </xsl:template>
</xsl:stylesheet>

xml:

<?xml version="1.0" encoding="utf-8" ?>
<xml>
  <date1>01/01/2001 00:00:00</date1>
  <date2>2/2/2002 00:00:00</date2>
</xml>