Coding in Tiers - Part I

using System;
using System.Reflection;
using System.Windows.Forms;

namespace Auto
{
	#region -- Automator --
	/// <summary>
	/// A utility class for auto populating windows forms.
	/// </summary>
	public sealed class Automator
	{
		#region -- Constructors --
		/// <summary>
		/// Create a new mediator for the specified form.
		/// </summary>
		/// <param name="winForm">The windows Form object</param>
		public Automator(Form winForm)
			:this(winForm, null)
		{
		}

		/// <summary>
		/// Create a new mediator for the specified form to store the
		/// object state.
		/// </summary>
		/// <param name="winForm">The windows Form object</param>
		/// <param name="state">The current state of the form</param>
		public Automator(Form winForm, object state)
		{
			this.winForm = winForm;
			this.state = state;
		}
		#endregion

		#region -- Properties --
		private object state;
		/// <summary>
		/// The current state of the object
		/// </summary>
		public object State
		{
			get
			{
				return this.state;
			}
			set
			{
				this.state = value;
			}
		}

		private Form winForm;
		/// <summary>
		/// The windows Form
		/// </summary>
		public Form WinForm
		{
			get
			{
				return this.winForm;
			}
		}
		#endregion

		#region -- Methods --
		/// <summary>
		/// Store the current state of the form
		/// </summary>
		public void Store()
		{
			Store(this.WinForm);
		}

		/// <summary>
		/// Restore the form to it's last state
		/// </summary>
		public void Restore()
		{
			Restore(this.WinForm);
		}
		
		/// <summary>
		/// Store the state of the control using the property on the
		/// State object by matching the name of the control with the
		/// name of the property. Type conversions will be performed
		/// on the value if necessary.
		/// </summary>
		/// <param name="control">The control whose state is to be stored</param>
		private void Store(Control control)
		{
			// Obtain the type of the State object
			Type type = this.State.GetType();

			// Check if the control has a valid name
			if(control.Name != null)
			{
				// Obtain the property whose name matches the control name
				PropertyInfo info = type.GetProperty(control.Name);

				// Does such a property exist?
				if(info != null)
				{
					// Set the property value corresponding to the value on the control
					info.SetValue(state, GetValue(info.PropertyType, control), null);
				}

				// Check if the control itself contains any nested controls
				Control.ControlCollection ctrls = control.Controls;

				// Iterate over the controls in the collection
				foreach (Control ctrl in ctrls)
				{
					// Store the state of the control
					Store(ctrl);
				}
			}
		}

		/// <summary>
		/// Restore the state of the control using the property on the
		/// State object by matching the name of the control with the
		/// name of the property.
		/// </summary>
		/// <param name="control">The control whose state is to be restored</param>
		private void Restore(Control control)
		{
			// Obtain the type of the State object
			Type type = this.State.GetType();

			// Check if the control has a valid name
			if(control.Name != null)
			{
				// Obtain the property whose name matches the control name
				PropertyInfo info = type.GetProperty(control.Name);

				if(info != null)
				{
					// Set the control value corresponding to the value on the property
					SetValue(control, info.GetValue(state, null));
				}

				// Check if the control itself contains any nested controls
				Control.ControlCollection ctrls = control.Controls;

				// Iterate over the controls in the collection
				foreach (Control ctrl in ctrls)
				{
					// Restore the state of the control
					Restore(ctrl);
				}
			}
		}

		/// <summary>
		/// Obtain the value object from the control
		/// </summary>
		/// <param name="type">The property type</param>
		/// <param name="control">The control from which the value has to be extracted</param>
		/// <returns>The value to be set</returns>
		private object GetValue(Type type, object control)
		{
			object src = null;

			switch(control.GetType().ToString())
			{
				case "System.Windows.Forms.TextBox":
					// Text from a text box
					src = ((TextBox)control).Text;
					break;
				case "System.Windows.Forms.ComboBox":
					// SelectedItem of a combo box
					src = ((ComboBox)control).SelectedItem;
					break;
				case "System.Windows.Forms.ListBox":
					// Single or Multiple values of a list box depending on SelectionMode
					ListBox list = (ListBox)control;

					// Check the list selection mode
					if(list.SelectionMode != SelectionMode.MultiSimple &&
						list.SelectionMode != SelectionMode.MultiExtended)
					{
						// Obtain the selected item
						src = list.SelectedItem;
					}
					else
					{
						// Obtain all the selected items
						ListBox.SelectedObjectCollection soc = list.SelectedItems;

						// Copy the selected values in an array
						string[] array = new string[soc.Count];
						soc.CopyTo(array, 0);

						// Set the values
						src = array;
					}
					break;
				case "System.Windows.Forms.CheckBox":
					// Checked state of a check box
					src = ((CheckBox)control).Checked;
					break;
				case "System.Windows.Forms.RadioButton":
					// Checked state of a radio button
					src = ((RadioButton)control).Checked;
					break;
				default:
					break;
			}

			// Perform any type conversions if necessary
			return ConvertValue(type, src);
		}

		/// <summary>
		/// Set the value on the control
		/// </summary>
		/// <param name="control">The control on which the value has to be set</param>
		/// <param name="obj">The value to be set</param>
		private void SetValue(object control, object obj)
		{
			// Obtain the type of control
			switch(control.GetType().ToString())
			{
				case "System.Windows.Forms.TextBox":
					// Text from a text box
					((TextBox)control).Text = Convert.ToString(obj);
					break;
				case "System.Windows.Forms.ComboBox":
					// SelectedItem of a combo box
					((ComboBox)control).SelectedItem = obj;
					break;
				case "System.Windows.Forms.ListBox":
					// Single or Multiple values of a list box depending on SelectionMode
					ListBox list = (ListBox) control;

					// Check the list selection mode
					if(list.SelectionMode != SelectionMode.MultiSimple &&
						list.SelectionMode != SelectionMode.MultiExtended)
					{
						// Set the selected item
						list.SelectedItem = obj;
					}
					else
					{
						// Iterate over the array
						foreach(object selected in (obj as object[]))
						{
							// Select the index of the list corresponding to the
							// value in the array
							list.SetSelected(list.Items.IndexOf(selected), true);
						}
					}
					break;
				case "System.Windows.Forms.CheckBox":
					// Checked state of a check box
					((CheckBox)control).Checked = Convert.ToBoolean(obj);
					break;
				case "System.Windows.Forms.RadioButton":
					// Checked state of a radio button
					((RadioButton)control).Checked = Convert.ToBoolean(obj);
					break;
				default:
					break;
			}
		}

		/// <summary>
		/// Perform type conversions if necessary
		/// </summary>
		/// <param name="type">The type to be compared</param>
		/// <param name="src">The source value</param>
		/// <returns>The value to be set</returns>
		private object ConvertValue(Type type, object src)
		{
			// Target value
			object dest = null;

			if(src != null)
			{
				// Pretty self explanatory!
				if(type == typeof(String))
				{
					dest = src;
				}
				else if(type == typeof(Boolean))
				{
					dest = Convert.ToBoolean(src);
				}
				else if(type == typeof(Byte))
				{
					dest = Convert.ToByte(src);
				}
				else if(type == typeof(Char))
				{
					dest = Convert.ToChar(src);
				}
				else if(type == typeof(DateTime))
				{
					dest = Convert.ToDateTime(src);
				}
				else if(type == typeof(Decimal))
				{
					dest = Convert.ToDecimal(src);
				}
				else if(type == typeof(Double))
				{
					dest = Convert.ToDouble(src);
				}
				else if(type == typeof(Int16))
				{
					dest = Convert.ToInt16(src);
				}
				else if(type == typeof(Int32))
				{
					dest = Convert.ToInt32(src);
				}
				else if(type == typeof(Int64))
				{
					dest = Convert.ToInt64(src);
				}
				else if(type == typeof(SByte))
				{
					dest = Convert.ToSByte(src);
				}
				else if(type == typeof(Single))
				{
					dest = Convert.ToSingle(src);
				}
				else if(type == typeof(UInt16))
				{
					dest = Convert.ToUInt16(src);
				}
				else if(type == typeof(UInt32))
				{
					dest = Convert.ToUInt32(src);
				}
				else if(type == typeof(UInt64))
				{
					dest = Convert.ToUInt64(src);
				}
				else
				{
					// Default if none match
					dest = src;
				}
			}

			// Return the value to be set
			return dest;
		}
		#endregion
	}
	#endregion
}