PropertyGrid and Drop Down properties

using System;
using System.Collections;
using System.ComponentModel;
using System.Windows.Forms;
using System.Reflection;
using System.Collections.Specialized;
using System.Drawing.Design;
using System.Drawing;
using System.Resources;
using System.Windows.Forms.Design;


namespace SampleClasses
{

	internal class HE_GlobalVars
	{
		internal static string[] _ListofRules;
		
	}

	public class ContrastEditor : UITypeEditor
	{
		public override UITypeEditorEditStyle GetEditStyle(
			ITypeDescriptorContext context)
		{
			return UITypeEditorEditStyle.DropDown;
		}

		public override object EditValue(ITypeDescriptorContext context,
			IServiceProvider provider, object value)
		{
			IWindowsFormsEditorService wfes = provider.GetService(
				typeof(IWindowsFormsEditorService)) as
				IWindowsFormsEditorService;
			
			if (wfes != null)
			{
				frmContrast _frmContrast = new frmContrast();

				_frmContrast.trackBar1.Value = (int) value;
				_frmContrast.BarValue = _frmContrast.trackBar1.Value;
				_frmContrast._wfes = wfes;
				
				wfes.DropDownControl(_frmContrast);
				value = _frmContrast.BarValue;

			}
			return value;
		}
	}
	
	public enum HE_SourceType {LAN, WebPage, FTP, eMail, OCR}
	public class SourceTypePropertyGridEditor : UITypeEditor
	{
		public override bool GetPaintValueSupported(ITypeDescriptorContext context)
		{
//Set to true to implement the PaintValue method
			return true;
		}

		public override void PaintValue(PaintValueEventArgs e)
		{	
			//Load SampleResources file
			string m = this.GetType().Module.Name;
			m = m.Substring(0, m.Length - 4);
			ResourceManager resourceManager =
				new ResourceManager (m + ".ResourceStrings.SampleResources", Assembly.GetExecutingAssembly());

			int i = (int)e.Value;
			string _SourceName = "";
			switch(i)       
			{         
				case ((int)HE_SourceType.LAN):			_SourceName = "LANTask";		break;   
				case ((int)HE_SourceType.WebPage):  _SourceName = "WebTask";		break;    
				case ((int)HE_SourceType.FTP):			_SourceName = "FTPTask";		break;    
				case ((int)HE_SourceType.eMail):		_SourceName = "eMailTask";	break;                     
				case ((int)HE_SourceType.OCR):			_SourceName = "OCRTask";		break;     
			}
			
			//Draw the corresponding image
			Bitmap newImage = (Bitmap)resourceManager.GetObject(_SourceName);
			Rectangle destRect = e.Bounds;
			newImage.MakeTransparent();
			e.Graphics.DrawImage(newImage, destRect);

		}
	}	

	public class RuleConverter : StringConverter
	{

		public override bool GetStandardValuesSupported(ITypeDescriptorContext context)
		{
			//true means show a combobox
			return true;
		}

		public override bool GetStandardValuesExclusive(ITypeDescriptorContext context)
		{
			//true will limit to list. false will show the list, but allow free-form entry
			return true;
		}

		public override
			System.ComponentModel.TypeConverter.StandardValuesCollection
			GetStandardValues(ITypeDescriptorContext context)
		{
			return new StandardValuesCollection(HE_GlobalVars._ListofRules);
		}

	}

	public class HE_Task
	{
		private string _Rule;
		private HE_SourceType _SourceType;
		private int _Contrast;

		[Browsable(true)]
		[TypeConverter(typeof(RuleConverter))]
		public string Rule
		{
		
			//When first loaded set property with the first item in the rule list.
			get	{
					string S = "";
					if (_Rule != null)
					{
						S = _Rule;
					}
					else
					{
						if (HE_GlobalVars._ListofRules.Length > 0)
						{
							//Sort the list before displaying it
							Array.Sort(HE_GlobalVars._ListofRules);

							S = HE_GlobalVars._ListofRules[0];
						}
					}

					return S;
				}
			set{ _Rule = value; }

		}

		[Editor(typeof(SourceTypePropertyGridEditor),
						typeof(System.Drawing.Design.UITypeEditor))]
		public		HE_SourceType		SourceType
		{
			get{return _SourceType;}
			set{_SourceType = value;}
		}

		[Editor(typeof(ContrastEditor),
			 typeof(System.Drawing.Design.UITypeEditor))]
		public		int	Contrast
		{
			get{return _Contrast;}
			set{_Contrast = value;}
		}
	}

	
}