An XML- and State Machine-based Design of a WinForms Control

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Data;
using System.Reflection;
using OGCLib;

//
// General Information about an assembly is controlled through the following 
// set of attributes. Change these attribute values to modify the information
// associated with an assembly.
//
[assembly: AssemblyTitle("OGCComboBoxLib")]
[assembly: AssemblyDescription("This assembly contains classes for the combo box element.")]
[assembly: AssemblyCompany("Igor Ladnik")]
[assembly: AssemblyProduct("Open Group Control")]

[assembly: AssemblyVersion("1.2.*")]

namespace OGCComboBoxLib
{
	///////////////////////////////////////////////////////////////////////////////////
	// Class CBComboBox
	///////////////////////////////////////////////////////////////////////////////////
	public class OGCComboBox : ComboBox, IElement
	{
		// Variables
		private int		  id;
		private OGControl ogControl = null;

		// Specify positions of element for hrizontal and vertical orientation of control
		private Point	  horizPosition;				
		private Point	  vertPosition;

		// Number of element's states
		private int		  statesMax = 0;

		// State Transition matrix
		private int[,]	  aiControlStateTransition = null;
		
		// false - if SetCurrentState(int currentState) method of element has not been called yet.
		// true  - otherwise
		private bool	  selectionChanged = false;
		private bool	  justStarted = true;

		// CONSTRUCTOR
		public OGCComboBox(OGControl ogControl)
		{
			this.ogControl = ogControl;
			Visible = false;
		}

		// METHODS

		// Virtual
		protected override void OnSelectionChangeCommitted(EventArgs ea)
		{
			selectionChanged = true;
		}

		protected override void OnSelectedValueChanged(EventArgs ea)
		{
			if (null != ogControl && selectionChanged)
			{
				ogControl.HitElement = this;
				ogControl.ChangeState(GetNewControlState());
			}

			selectionChanged = false;
		}

		// IElement implementation methods
		public void Initialize(string name, Point horizPosition, Point vertPosition, Size size)
		{
			if (null != ogControl)
			{
				Name = name;
				id = ogControl.VisualElementsNumber;
				this.horizPosition = horizPosition;
				this.vertPosition = vertPosition;
				
				this.horizPosition.Y += ogControl.CaptionHeight; 
				this.vertPosition.Y += ogControl.CaptionHeight; 			
				
				UpdateGeometry();

				Size = size;
				Visible = true;
			}
		}

		public void SetControlStateTransitionElement(int currCtrlState, int currState, 
			int nextCtrlState)
		{
			if (null == aiControlStateTransition)
			{
				aiControlStateTransition = new int[ogControl.ControlStatesMax, statesMax];
				for (int i=0; i<ogControl.ControlStatesMax; i++)
					for (int j=0; j<statesMax; j++)
						aiControlStateTransition[i, j] = -1;
			}

			aiControlStateTransition[currCtrlState, currState] = nextCtrlState;
		}

		public int AddState(string name, string pictureName, string ext)
		{
			Items.Add(name);
			return ++statesMax;
		}

		public int GetNewControlState()
		{
			if (null != ogControl && null != aiControlStateTransition)
				return aiControlStateTransition[ogControl.CurrentState, SelectedIndex];
	
			return -1;
		}

		public void SetCurrentState(int currentState)
		{
			if (-1 < currentState && Items.Count > currentState)
			{
				SelectedIndex = currentState;
				Update();
			}

			if (-1 == currentState && justStarted)
			{	
				SelectedIndex = 0;
				Update();
			}

			justStarted = false;
		}

		public bool HasImage()
		{
			return false;
		}

		public string GetName()
		{
			return Name;
		}

		public int GetId()
		{
			return id;
		}

		public string GetStateName()
		{
			return SelectedItem.ToString();
		}

		public int GetNextStatesNum()
		{
			return Items.Count;
		}

		public void UpdateGeometry()
		{
			Point position = OGCLib.Orientation.Horizontal == ogControl.GetOrientation()
				? horizPosition : vertPosition;

			Left = position.X;
			Top = position.Y;
		}

		public void Draw(Graphics grfx, bool show)
		{
			Visible = show;
		}

		public bool HitTest(MouseEventArgs mea)
		{
			return false;
		}
	}

	///////////////////////////////////////////////////////////////////////////////////
	// Class Factory
	///////////////////////////////////////////////////////////////////////////////////
	public class Factory : IFactory
	{
		public IElement CreateElement(OGControl ogControl)
		{
			OGCComboBox comboBox = new OGCComboBox(ogControl);
			ogControl.Controls.Add(comboBox);
			return comboBox;
		}	
	}
}