gistfile1.txt

if (KeyboardType == UIKeyboardType.NumberPad)
			{
				NSNotificationCenter.DefaultCenter.AddObserver (  
				    "UIKeyboardDidShowNotification", (notification) => {  
						UIButton doneButton = new UIButton(new RectangleF(0, 163, 106, 53));
						doneButton.ButtonType = UIButtonType.Custom;
						doneButton.SetTitle("Done", UIControlState.Normal);
						UIWindow window = UIApplication.SharedApplication.Windows[0];
						UIView keyboardView;
						foreach(var v in window.Subviews)
						{
							if (v is UIKit.UIKeyboard)
							{
								
							}
						}
				        Console.WriteLine ("Keyboard went up");  
				    }); 
				
			}