/// <summary>获得合并区域宽度</summary>
public static double GetMergedRegionWidthInPoints(this ISheet sheet, CellRangeAddress region)
{
var width = 0.0;
for (int i = region.FirstColumn; i <= region.LastColumn; i++)
{
width += sheet.GetColumnWidthInPoints(i);
}
return(width);
}