Hi Steve,

Well, that's a pretty clear indication that this is a threading issue. You say you are updaing the data source in a thread-safe manner. If you are updating the grid's data source on a thread other than the UI thread, then that's not safe under any circumstances because the data source may fire events that the grid is responding to on another thread. You must always suspend the notifications.

Hi Mike,

The method you provided works well, but I am still seeing the same exception.  I did notice one thing, though.  We have multiple threads updating the underlying datasource in a thread-safe manner.  Each update to the datasource conditionally calls SuspendBindingNotifications depending on the number of updates being done (let's say, more than 10).  If I remove that condition, and always suspend the binding notifications, I do not run into any unexpected exceptions with the stacktrace above.  When I include the condition to not suspend the binding notifications, I am able to reproduce the error after waiting an undeterministic amount of time.  The downside to always suspending the binding notifications is that the overall performance seems slower.

I know this is a rather vague description of the symptoms, but just throwing it out there.

Thanks for your help,

Steve

If you are concerned about getting the best possible efficiency, then you can use the UIElements of the grid directly. Here's some code that uses the UIElements to get the rows in the visible area. This code is assuming that there is only one ScrollRegion in the grid and that thereare no GroupByRows. 

private List<UltraGridRow> GetVisibleRows(UltraGrid grid)
        {
            List<UltraGridRow> rows = new List<UltraGridRow>();

            UIElement element = this.ultraGrid1.DisplayLayout.UIElement;
            if (element != null)
            {
                element = element.GetDescendant(typeof(DataAreaUIElement));
                if (element != null)
                {
                    element = element.GetDescendant(typeof(RowColRegionIntersectionUIElement));
                    if (element != null)
                    {
                        foreach (UIElement childElement in element.ChildElements)
                        {
                            if (childElement is RowUIElement)
                            {
                                UltraGridRow row = childElement.GetContext() as UltraGridRow;
                                if (row != null)
                                    rows.Add(row);
                            }
                        }
                    }
                }
            }

            return rows;
        }

Hi Mike, 

The timer is a Windwos.Forms.Timer.

In the body of the timer, I try to iterate through the VisibleRows collection of the ActiveRowScrollRegion.  Based on the time, we fade the color of the some of the cells in the row.  So, each iteration either calls ultraGridRow.Cells["column1"].Refresh() or sets ultraGridRow.Cells["column2"].ForeColor.  Is there a better approach to force a repaint of the cells? 

Unfortunately, I can't reproduce this reliably.  I have to run performance testing tool that creates a large amount of updates to the client application.

I am also running v7.2 of the toolset.  Do you think v7.3 would give me better results?

Thanks!

Steve