A Practical Use of the MVC Pattern

using System;
using System.Data;
using MvcExample.EventHandlers;
using WinFormsEx;

namespace MvcExample.Models
{
	public abstract class BaseModel
	{
		/// <summary>
		/// Event fired when the model is finished calculating/processing the data.
		/// </summary>
		public event EventHandler ModelChanged;

		/// <summary>
		/// Event fired when the model is calculating the data to notify the view
		/// about its progress.
		/// </summary>
		public event ProgressEventHandler ModelProgress;

		#region protected members
		protected BackgroundWorker backgroundWorker;
		protected DataSet ds;
		#endregion protected members

		#region constructor
		protected BaseModel()
		{
			ds = new DataSet();
			backgroundWorker = new BackgroundWorker();

			backgroundWorker.WorkerReportsProgress = false;
			backgroundWorker.WorkerSupportsCancellation = true;
		}
		#endregion constructor

		#region public abstract methods
		public abstract void GenerateReport();
		#endregion public abstract methods

		#region public methods
		/// <summary>
		/// Returns the report data.
		/// </summary>
		public DataSet QueryModel()
		{
			return ds;
		}

		public void CancelBackgroundWorker()
		{
			backgroundWorker.CancelAsync();
		}
		#endregion public methods

		#region event firing methods
		protected void Fire_ModelChanged(object sender, RunWorkerCompletedEventArgs ea)
		{
			BackgroundWorker bw = sender as BackgroundWorker;
			if (bw != null)
				bw.RunWorkerCompleted -= new RunWorkerCompletedEventHandler(Fire_ModelChanged);

			if (ModelChanged != null)
				ModelChanged(this, EventArgs.Empty);
		}

		protected void Fire_ModelProgress(object sender, int percent)
		{
			if (ModelProgress != null)
				ModelProgress(this, percent);
		}
		#endregion event firing methods
	}
}