app-start.cs

using System;
using System.Configuration;
using Microsoft.Practices.Unity;
using Microsoft.Practices.Unity.Configuration;
 
namespace Canberra.InterfacesDemo.WebApp
{
  public class Global : System.Web.HttpApplication
  {
    public static UnityContainer Container;
 
    protected void Application_Start(object sender, EventArgs e)
    {
      Container = new UnityContainer();
      var section = (UnityConfigurationSection)ConfigurationManager
      .GetSection("unity");
      section.Configure(Container);
    }
  }
}

CustomersReminder1.cs

namespace Canberra.InterfacesDemo.Lib
{
  public class CustomersReminder
  {
    public void Remind(ICustomersFetcher customersFetcher, IEmailSender emailSender)
    {
      foreach (var customer in customersFetcher.GetSleepingCustomers())
      {
        emailSender.SendRemindMessage(customer.FirstName, customer.LastName, customer.EmailAddress);
      }
    }
  }
}

example1.cs

namespace Canberra.InterfacesDemo.Lib
{
  public class CustomersReminder
  {
    public void Remind(ICustomersFetcher customersFetcher, IEmailSender emailSender)
    {
      foreach (var customer in customersFetcher.GetSleepingCustomers())
      {
        emailSender.SendRemindMessage(customer.FirstName, customer.LastName, customer.EmailAddress);
      }
    }
  }
}

ioc-example1.cs

var container = new UnityContainer();
var section = (UnityConfigurationSection)ConfigurationManager.GetSection("unity");
section.Configure(container);
 
var customersReminder = new CustomersReminder();
customersReminder.Remind(new CustomersFetcher(), container.Resolve<IEmailSender>());

ioc-example2.cs

var customersReminder = new CustomersReminder();
customersReminder.Remind(new CustomersFetcher(), 
    Global.Container.Resolve<IEmailSender>());

manual-instance.cs

var customersReminder = new CustomersReminder();
customersReminder.Remind(new CustomersFetcher(), new EmailSender());

unity-config.xml

<?xml version="1.0"?>
<configuration>
  <configSections>
    <section
    name="unity"
    type="Microsoft.Practices.Unity.Configuration.UnityConfigurationSection, 
      Microsoft.Practices.Unity.Configuration" 
  />
  </configSections>  
  <unity>
    <typeAliases>
      <typeAlias
    alias="IEmailSender"
    type="Canberra.InterfacesDemo.Lib.IEmailSender, 
      Canberra.InterfacesDemo.Lib" 
    />
      <typeAlias
    alias="EmailSender"
    type="MyMail.EmailSender, MyMail"
    />
    </typeAliases>
    <containers>
      <container>
        <types>
          <type type="IEmailSender" mapTo="EmailSender"/>          
        </types>
      </container>
    </containers>
  </unity>
</configuration>