/// <summary>
/// adds a merged region of cells (hence those cells form one)
/// </summary>
/// <param name="region">region (rowfrom/colfrom-rowto/colto) to merge</param>
/// <returns>index of this region</returns>
public int AddMergedRegion(NPOI.SS.Util.CellRangeAddress region)
{
region.Validate(SpreadsheetVersion.EXCEL97);
// throw IllegalStateException if the argument CellRangeAddress intersects with
// a multi-cell array formula defined in this sheet
ValidateArrayFormulas(region);
return _sheet.AddMergedRegion(region.FirstRow,
region.FirstColumn,
region.LastRow,
region.LastColumn);
}
