Multiline Edit Element for MonoTouch.Dialog

multiline.cs

using System;
using MonoTouch.Dialog;
using MonoTouch.UIKit;
using MonoTouch.Foundation;
using System.Drawing;
using MonoTouch.CoreGraphics;

namespace DeadDrop
{
	
	
	public class MultilineEditElement : StringElement
	{
		static NSString skey = new NSString("multilineeditelement");
		public MultilineEditElement(string caption, string val) : base(caption, val)
		{
			
		}
		
		class MyViewController : UIViewController {
			MultilineEditElement container;
			UITextView editbox;
			
			
			private const float PortratKeyboardHeight = 216;
			private const float LandscapeKeyboardHeight = 162;
			private RootElement rootElement;
			
			public MyViewController (MultilineEditElement container, RootElement rootElement)
			{
			
				this.container = container;
				this.rootElement = rootElement;
				
				NavigationItem.Title = container.Caption;
				
				editbox = new UITextView();
				editbox.Text = container.Value;
				editbox.Font = UIFont.SystemFontOfSize(17f);
				
				this.View.Add(editbox);
				
			}
			
			public override void ViewDidAppear (bool animated)
			{
				base.ViewDidAppear (animated);
				
				
				SetViewOrientationAndSize();
				editbox.BecomeFirstResponder();
			}
			
			public override void ViewWillDisappear (bool animated)
			{
				base.ViewWillDisappear (animated);
				container.Value = editbox.Text;
				rootElement.Reload(container, UITableViewRowAnimation.None);
				
			}
			
			public override void DidRotate (UIInterfaceOrientation fromInterfaceOrientation)
			{
				
				base.DidRotate (fromInterfaceOrientation);
				
				SetViewOrientationAndSize();
				
				
			}
			
			private void SetViewOrientationAndSize()
			{
				
				float keyboardHeight = 0;
				
				switch (UIDevice.CurrentDevice.Orientation)
				{
					case UIDeviceOrientation.LandscapeLeft:
					case UIDeviceOrientation.LandscapeRight:
						 keyboardHeight = LandscapeKeyboardHeight;
						break;
					case UIDeviceOrientation.Portrait:
					case UIDeviceOrientation.PortraitUpsideDown:
						 keyboardHeight = PortratKeyboardHeight;
						
						break;
				}
				
				//Console.WriteLine("View: X: {0} Y: {1} W: {2} H:{3}", View.Frame.X, View.Frame.Y, View.Frame.Width, View.Frame.Height);
				
				RectangleF viewRect = new RectangleF(View.Frame.X, View.Frame.Y, View.Frame.Width, View.Frame.Height - keyboardHeight + 50);
				
				// 50 == we have a tab bar at the bottom!! :(
				
				editbox.Frame = viewRect;
			}
			
		
			
			public override bool ShouldAutorotateToInterfaceOrientation (UIInterfaceOrientation toInterfaceOrientation)
			{

				return true;
			}
			
			
		}
		
		
		
		
		
		public override UITableViewCell GetCell (UITableView tv)
		{
			var cell = tv.DequeueReusableCell (skey);
			if (cell == null){
				
				cell = new UITableViewCell (Value == null ? UITableViewCellStyle.Default : UITableViewCellStyle.Value1, skey);
				cell.SelectionStyle =  UITableViewCellSelectionStyle.Blue;
			}
			cell.Accessory = UITableViewCellAccessory.None;
			cell.TextLabel.Text = Caption;
			cell.TextLabel.TextAlignment = Alignment;
			
			
			// The check is needed because the cell might have been recycled.
			if (cell.DetailTextLabel != null)
			{
				cell.DetailTextLabel.Text = Value == null ? "" : Value;
				cell.DetailTextLabel.AdjustsFontSizeToFitWidth = true;
				cell.DetailTextLabel.MinimumFontSize = 13.0f;
			
			}
			
			
			
			return cell;
		}
		
		public override void Selected (DialogViewController dvc, UITableView tableView, NSIndexPath path)
		{
			dvc.ActivateController (new MyViewController (this, dvc.Root));
		}
		
	}
    }
}

Hi, how would you create the Changed event?
I need to have something like

MultilineEditElement myElement = new MultilineEditElement ("Example", "");
myElement.Changed += myChangedEvent;