/*
         * Demonstrate the CellEndEdit event by validating that the 
         * user entered a valid integer > 0.
         */
        private void workbookView_CellEndEdit(object sender, CellEndEditEventArgs e)
        {
            // Acquire a lock on the workbook set.
            workbookView.GetLock();
            try
            {
                // Get a reference to the active worksheet's cells.
                SpreadsheetGear.IRange cells = (await LockedWorkbookView.GetActiveWorksheetAsync()).Cells;
 
                // Check if the correct cell is selected.
                if (workbookView.RangeSelection.Equals(cells["B1"]))
                {
                    // Try to convert the entry to an integer.
                    int result;
                    bool validInt = Int32.TryParse(e.Entry, out result);
 
                    // Check if the entry is valid.
                    if (!validInt || result <= 0)
                    {
                        // Show a message and cancel CellEndEdit.
                        MessageBox.Show("The entry must be an integer greater than 0.", 
                            "Entry Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                        e.Cancel = true;
                    }
                }
            }
            finally
            {
                // Release the lock on the workbook set.
                workbookView.ReleaseLock();
            }
        }