protected internal bool IsValidCell(int row, int column) { if (this.TableModel != null && this.ColumnModel != null) { if (row >= 0 && row < this.TableModel.Rows.Count) { if (column >= 0 && column < this.ColumnModel.Columns.Count) { return (this.TableModel.Rows[row].Cells[column] != null); } } } return false; }