>>>>Well... I found two errors to start with.
>>>>
>>>>

     private void NotifyPropertyChanged(String info)
>>>>        {
>>>>        if (PropertyChanged != null)
>>>>          {
>>>>          PropertyChanged(this, new PropertyChangedEventArgs(info));
>>>>          //CollectionChanged was null commented it off
>>>>          //CollectionChanged(this, new CollectionChangeEventArgs(CollectionChangeAction.Refresh, this.HoleList));
>>>>          }
>>>>        }

>>>>
>>>>Second was that repaint screen was not getting called. You are binding to CurrentHolePattern so:
>>>>
>>>>

CurrentHolePattern.PropertyChanged += new PropertyChangedEventHandler(CurrentHolePattern_PropertyChanged);

>>>>
>>>>This looks like it works:
>>>>
>>>>

    public Window1()
>>>>      {
>>>>
>>>>      HolePatterns = new ObservableCollection<HolePattern>();
>>>>      HolePatterns.CollectionChanged += new NotifyCollectionChangedEventHandler(HolePatterns_CollectionChanged);
>>>>
>>>>      CurrentHolePattern = new HolePattern();
>>>>      CurrentHolePattern.PatternName = "Test Pattern Name";
>>>>
>>>>      //-- Set some default values for the UI
>>>>      CurrentHolePattern.BoltCirDia = 12.0;
>>>>      CurrentHolePattern.HoleCount = 6;
>>>>      CurrentHolePattern.StartAngle = 0;
>>>>
>>>>      HolePatterns.Add(CurrentHolePattern);
>>>>
>>>>      InitializeComponent();
>>>>      CurrentHolePattern.PropertyChanged += new PropertyChangedEventHandler(CurrentHolePattern_PropertyChanged);
>>>>
>>>>      SketchX0 = canvas1.Width / 2;
>>>>      SketchY0 = canvas1.Height / 2;
>>>>      SketchBoltCirRad = canvas1.Width / 2 * .7;
>>>>
>>>>      CoordinateGrid.ItemsSource = CurrentHolePattern.HoleList;
>>>>
>>>>      RedrawScreen();
>>>>      }
>>>>
>>>>    void CurrentHolePattern_PropertyChanged(object sender, PropertyChangedEventArgs e)
>>>>      {
>>>>      RedrawScreen();
>>>>      //RepaintScreen();  Repaint doesn't add new holes.
>>>>      }
>>>>

>>>
>>>Dang. Just read this. I pulled in Matt's code last night and had made *exactly* the same changes that you pointed out. But then it would not run - I got a XMLParseException:
>>>Cannot create instance of 'Window1' defined in assembly 'WpfApplication1, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null'. Exception has been thrown by the target of an invocation. Error in markup file 'Window1.xaml' Line 1 Position 9.
>>>
>>>Didn't have time to look at it any more and don't now either but it's still giving that error unless the RedrawScreen() line is commented out in the event handler.
>>>???
>>>Regards,
>>>Viv
>>
>>Did you put the
>>
>>CurrentHolePattern.PropertyChanged += new PropertyChangedEventHandler(CurrentHolePattern_PropertyChanged);
>>
>>before the
>>
>>InitializeComponent();
>>
>>by any chance? That will throw that error.
>
>Very possibly. But, as I just mentioned to Matt, without thinking I pasted his newer version over the top of the one with my changes so now I'll never know for sure. IAC I'll know what to check if I make the same mistake in the future!
>Thanks,
>Viv

The only reason it came to mind is that I made that mistake myself.<g>