A Beginner's Tutorial for Understanding Templated User Controls

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.ComponentModel;

public partial class TemplateUCtrl : System.Web.UI.UserControl 
{
    //the template control specific stuff
    private ITemplate personTemplate;
 
    //the controls data specific stuff
    private PersonItem personItem = null;

    protected void Page_Init(object sender, EventArgs e)
    {
        //lets first clear the placeholders to attach then to new data
        this.phdPerson.Controls.Clear();     

        //but what if the user forgot to send the user information   
        if (Person == null)
        {  
            phdPerson.Controls.Add(new LiteralControl("Please attach the control with a person object."));         
        }
        else
        {
            //check if the templates are null we want to use simple literal
            //The user wants the default representation of the control
            if (PersonTemplate == null)
            {
                //Lets show the default representation of the control
                phdPerson.Controls.Add(new LiteralControl("<Strong>First Name: </strong>"));
                phdPerson.Controls.Add(new LiteralControl(Person.FirstName));
                phdPerson.Controls.Add(new LiteralControl("<br/>"));
                phdPerson.Controls.Add(new LiteralControl("<Strong>Last Name: </strong>"));
                phdPerson.Controls.Add(new LiteralControl(Person.LastName));
                phdPerson.Controls.Add(new LiteralControl("<br/>"));
                phdPerson.Controls.Add(new LiteralControl("<Strong>Age: </strong>"));
                phdPerson.Controls.Add(new LiteralControl(Person.Age.ToString()));
            }
            else
            {
                PersonItemContainer container = new PersonItemContainer(this.Person);
                this.PersonTemplate.InstantiateIn(container);
                phdPerson.Controls.Add(container);
            }
        }
    }

    [PersistenceMode(PersistenceMode.InnerProperty)]
    [TemplateContainer(typeof(PersonItemContainer))]
    public ITemplate PersonTemplate
    {
        get
        {
            return personTemplate;
        }
        set
        {
            personTemplate = value;
        }
    }

    public PersonItem Person
    {
        get
        {
            return personItem;
        }
        set
        {
            personItem = value;
        }
    }    
}