XlsFile.ColCountOnlyData Property
While ExcelFile.ColCount will return the maximum column including both data and formatted columns, this method doesn't include formatted columns, only cells with data, and it is normally what you need to use.
Important: This method includes blank formatted cells. See The Maximum Used Column On A Sheet
Syntax
Namespace: FlexCel.XlsAdapter
public override Int32 ColCountOnlyData { get; }