SharePoint 2010 : Call server side function from XSL.

Goal

To use a server side function from a XSL used in a web part.

Solution

It is simple to use a server side function. Just need to make sure the dll should be deployed in GAC. In this example I created a class with name "ClassName", the project name is "SampleApplication". Deployed the dll in GAC. Modify the XSL head and add xmlns:helper="SampleApplication.ClassName" on the head. "helper" is like an tag which will point to the class.

XSL

<xsl:stylesheet 
  version="1.0" 
  exclude-result-prefixes="x d xsl msxsl cmswrt helper"
  xmlns:x="http://www.w3.org/2001/XMLSchema" 
  xmlns:d="http://schemas.microsoft.com/sharepoint/dsp" 
  xmlns:ddwrt="http://schemas.microsoft.com/WebParts/v2/DataView/runtime"
  xmlns:cmswrt="http://schemas.microsoft.com/WebParts/v3/Publishing/runtime"
  xmlns:xsl="http://www.w3.org/1999/XSL/Transform" xmlns:msxsl="urn:schemas-microsoft-com:xslt"
  xmlns:helper="SampleApplication.ClassName">

SampleApplication.ClassName

#region System
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
#endregion

namespace SampleApplication
{
    public class ClassName
    {
        #region Properties
        
        /// <summary>
        /// Name 
        /// </summary>
        private static string Name = "Maulik Dhorajia";
        
        /// <summary>
        /// Today Date
        /// </summary>
        private static string TodayDate = System.DateTime.Now.ToString();

        #endregion

        /// <summary>
        /// Gets the property
        /// </summary>
        /// <param name="propertyKey"></param>
        /// <returns></returns>
        public static string GetProperty(string propertyKey)
        {
            if (propertyKey == "Name")
            {
                return Name;
            }
            else if (propertyKey == "TodayDate")
            {
                return TodayDate;
            }
            else 
            {
                return "";
            }
        }
    }
}

Calling the function from XSL

<xsl:value-of select="helper:GetLabel('Name')"/>
<xsl:value-of select="helper:GetLabel('TodayDate')"/>

This should be all to show the stuff on the page. Let me know if this helped.