Formatting and styling

Cell styling is accessed by the Style property of a range. You can easily style your spreadsheets by using the indexer of the Cells property decribed above. Lets say you want to set the numberformat of a range...

worksheet.Cells["C2:C5"].Style.Numberformat.Format = "#,##0";

...or you want to set the header row to bold and dark background and white font...

using (var range = worksheet.Cells[1, 1, 1, 5])  //Address "A1:A5"
{
    range.Style.Font.Bold = true;
    range.Style.Fill.PatternType = ExcelFillStyle.Solid;
    range.Style.Fill.BackgroundColor.SetColor(Color.DarkBlue);
    range.Style.Font.Color.SetColor(Color.White);
}

To see the some real code showing cell access and styling, look into the sample project, for example sample 1-.NET Framework or sample 1-.NET Core

You can also create your own named styles, using the Workbook.Style.CreateNamedStyle method and the ExcelRange.StyleName property. As shown in Sample 20-.NET Framework or sample 6-.NET Core...

            //Add a HyperLink to the statistics sheet. 
            var namedStyle = pck.Workbook.Styles.CreateNamedStyle("HyperLink");  
            namedStyle.Style.Font.UnderLine = true;
            namedStyle.Style.Font.Color.SetColor(Color.Blue);
            ws.Cells["K13"].Hyperlink = new ExcelHyperLink("Statistics!A1", "Statistics");
            ws.Cells["K13"].StyleName = "HyperLink";