gistfile1.cs

List<string> buttons = new List<string>();
			
			
			if (UIImagePickerController.IsCameraDeviceAvailable(UIImagePickerControllerCameraDevice.Rear))
			{
				hasPhoto = true;
				buttons.Add("Take a photo");
			} 
			hasExisting = true;
			buttons.Add("Choose Existing");
			if (SourceImage != null)
			{
				hasCurrent = true;
				buttons.Add("View current image");
			}
			buttons.Add("Cancel");
			
			sheet = new UIActionSheet("", null, null, null, buttons.ToArray());
			sheet.Clicked += delegate(object sender, UIButtonEventArgs e) {
				
				if (e.ButtonIndex == sheet.CancelButtonIndex) 
				{
					if (ImageSelected != null) ImageSelected();
					return;
				}
				
				//lots of working code, based on e.ButtonIndex
				
			};
			
			sheet.CancelButtonIndex = buttons.Count-1;
			sheet.ShowInView(ParentView.View);