Implementing Model-View-Presenter in ASP.NET

using System;
using System.Web.UI.WebControls;
using Presentation;
using Presentation.Interfaces;

/// <remarks>
///		Class Views_CustomersView is our ICustomerView. It is the View in the event driven
///		MVP relationship. Since this is the view in the event driven MVP, it knows nothing 
///		about its Presenter. The View initializer (ASPX) creates the MVP relationship. 
///		The view (Views_CustomersView) only raises events when certain actions occur. The view
///		is then told what to do.
/// 
///		Do use a protected virtual method to raise each event. This is only applicable to unsealed classes, 
///		not to structs or sealed classes.
/// 
///		For each event, include a corresponding protected virtual method  that raises the event. 
///		The purpose of the method is to provide a way for a derived class to handle the event using an 
///		override. Overriding is a more flexible, faster, and a more natural way to handle base class events 
///		in derived classes. The name of the method is should start with �On� and be followed with the name of the event.
/// </remarks>
public partial class Views_CustomersView : System.Web.UI.UserControl, ICustomersView
{
	protected override void OnLoad(EventArgs e)
	{
		EventHandler<SingleValueEventArgs<bool>> eventHandler = OnViewLoad;
		if (eventHandler != null)
		{
			// Invoke our delegate
			eventHandler(this, new SingleValueEventArgs<bool>(Page.IsPostBack));
		}

		base.OnLoad(e);
	}

	#region ICustomersView Members

	public event EventHandler<SingleValueEventArgs<bool>> OnViewLoad;
	public event EventHandler<SingleValueEventArgs<string>> RequestCustomerDetails;
	public event EventHandler<SingleValueEventArgs<string>> RequestCustomerEdit;
	
	public void SetCustomers(System.Data.IDataReader customerReader)
	{
		ddlCustomers.DataSource = customerReader;
		ddlCustomers.DataValueField = "CustomerID";
		ddlCustomers.DataTextField = "ContactName";
		ddlCustomers.DataBind();
		ddlCustomers.Items.Insert(0, new ListItem("Select Customers", "0"));
	}

	public void SetCustomerDetails(Model.Data.Interfaces.ICustomer customer)
	{
		if(customer == null)
		{
			lblAddress.Text = string.Empty;
			lblCity.Text = string.Empty;
			lblCompanyName.Text = string.Empty;
			lblContactName.Text = string.Empty;
			lblContactTitle.Text = string.Empty;
			lblCountry.Text = string.Empty;
			lblCustomerID.Text = string.Empty;
			lblFax.Text = string.Empty;
			lblPhone.Text = string.Empty;
			lblPostalCode.Text = string.Empty;
			lblRegion.Text = string.Empty;
		}
		else
		{
			lblAddress.Text = customer.Address;
			lblCity.Text = customer.City;
			lblCompanyName.Text = customer.CompanyName;
			lblContactName.Text = customer.ContactName;
			lblContactTitle.Text = customer.ContactTitle;
			lblCountry.Text = customer.Country;
			lblCustomerID.Text = customer.CustomerID.ToString();
			lblFax.Text = customer.Fax;
			lblPhone.Text = customer.Phone;
			lblPostalCode.Text = customer.PostalCode;
			lblRegion.Text = customer.Region;
		}
	}

	public void SetRefreshTime(DateTime dateTime)
	{
		lblTime.Text = dateTime.ToString();
	}

	#endregion

	protected void ddlCustomers_SelectedIndexChanged(object sender, EventArgs e)
	{
		// Raise our event
		OnRequestCustomerDetails(GetSelectedCustomerID());
	}

	protected void btnEdit_Click(object sender, EventArgs e)
	{
		// Raise our event
		OnRequestCustomerEdit(GetSelectedCustomerID());
	}

	/// <summary>
	///		Raise the RequestCustomerDetails event by invoking
	///		the delegates.
	/// </summary>
	/// <param name="customerID">string customerID</param>
	public virtual void OnRequestCustomerDetails(string customerID)
	{
		EventHandler<SingleValueEventArgs<string>> eventHandler = RequestCustomerDetails;
		if (eventHandler != null)
		{
			eventHandler(this, GetCustomerEventArgs(customerID));
		}
	}

	/// <summary>
	///		Raise the RequestCustomerEdit event by invoking
	///		the delegates.
	/// </summary>
	/// <param name="customerID">string customerID</param>
	public virtual void OnRequestCustomerEdit(string customerID)
	{
		EventHandler<SingleValueEventArgs<string>> eventHandler = RequestCustomerEdit;
		if (eventHandler != null)
		{
			eventHandler(this, GetCustomerEventArgs(customerID));
		}
	}

	private string GetSelectedCustomerID()
	{
		return ddlCustomers.SelectedValue;
	}

	private SingleValueEventArgs<string> GetCustomerEventArgs(string customerID)
	{
		return new SingleValueEventArgs<string>(customerID);
	}
}