WPF Control Factory

using System;
using System.Windows.Controls;
using Pfz.DataTypes;

namespace Pfz.WpfControls
{
	/// <summary>
	/// Control used to edit Times without dates.
	/// </summary>
	public class TimeControl:
		UserControl,
		IValueControl,
		IValueContainer<Time>,
		IValueContainer<Time?>,
		IHasPreferredDataType
	{
		private ComboBox fComboHour = new ComboBox { Width = 50 };
		private ComboBox fComboMinute = new ComboBox { Width = 50 };
		private ComboBox fComboSecond = new ComboBox { Width = 50 };
		
		/// <summary>
		/// Creates a new TimeControl.
		/// </summary>
		public TimeControl()
		{
			var stackPanel = new StackPanel();
			stackPanel.Orientation = Orientation.Horizontal;
			
			var gridChildren = stackPanel.Children;
			gridChildren.Add(fComboHour);
			gridChildren.Add(fComboMinute);
			gridChildren.Add(fComboSecond);
			
			p_AddValues(fComboHour, 24);
			p_AddValues(fComboMinute, 60);
			p_AddValues(fComboSecond, 60);
			
			Content = stackPanel;
		}

		private void p_AddValues(ComboBox combo, int count)
		{
			var items = combo.Items;
			for (int i=0; i<count; i++)
				items.Add(i);
		}
	
		private Type fPreferredDataType = typeof(Time);
		/// <summary>
		/// Gets or sets the preferred type for this control.
		/// </summary>
		public Type PreferredDataType
		{
			get
			{
				return fPreferredDataType;
			}
			set
			{
				if (value == fPreferredDataType)
					return;
				
				if (value == typeof(Time))
				{
					fComboHour.Items.RemoveAt(0);
					fPreferredDataType = value;
					return;
				}
				
				if (value == typeof(Time?))
				{
					fComboHour.Items.Insert(0, "");
					fPreferredDataType = value;
					return;
				}
				
				throw new ArgumentException("PreferredDataType must be Time or Nullable<Time>.");
			}
		}

		/// <summary>
		/// Clears the value of this control.
		/// </summary>
		public void Clear()
		{
			fComboHour.SelectedIndex = 0;
			fComboMinute.SelectedIndex = 0;
			fComboSecond.SelectedIndex = 0;
		}

		/// <summary>
		/// Gets or sets a value indicating if this control is read-only.
		/// </summary>
		public bool IsReadOnly
		{
			get
			{
				return !fComboHour.IsEnabled;
			}
			set
			{
				fComboHour.IsEnabled = !value;
				fComboMinute.IsEnabled = !value;
				fComboSecond.IsEnabled = !value;
			}
		}

		/// <summary>
		/// Gets or sets the value of this control.
		/// </summary>
		public Time? Value
		{
			get
			{
				var hour = fComboHour.SelectedValue;
				
				if (hour == null || hour.Equals(""))
					return null;
				
				return new Time(Convert.ToInt32(hour), fComboMinute.SelectedIndex, fComboSecond.SelectedIndex, 0);
			}
			set
			{
				if (!value.HasValue)
				{
					Clear();
					return;
				}
				
				var time = value.Value;
				fComboHour.SelectedValue = time.Hour;
				fComboMinute.SelectedIndex = time.Minute;
				fComboSecond.SelectedIndex = time.Second;
			}
		}
		
		#region IValueContainer Members
			object IValueContainer.Value
			{
				get
				{
					return Value;
				}
				set
				{
					Value = (Time?)value;
				}
			}
		#endregion
		#region IValueContainer<Time> Members
			Time IValueContainer<Time>.Value
			{
				get
				{
					return (Time)Value;
				}
				set
				{
					Value = value;
				}
			}
		#endregion
	}
}