The sample demonstrates how to set background color in Excel workbook via Spire.XLS.

using System.Drawing;

using Spire.Xls;

namespace BackgrandColor
{
    class Program
    {
        static void Main(string[] args)
        {
            Workbook workbook = new Workbook();
            workbook.LoadFromFile(@"..\..\..\..\Data\country.xls",ExcelVersion.Version97to2003);
            Worksheet worksheet = workbook.Worksheets[0];

            //set the backgroundcolor=LightBlue of Range["A2:E9"]
            worksheet.Range["A2:E9"].Style.Color = Color.LightBlue;

            //set the backgroundcolor=Silver of Range["A11:E18"]
            worksheet.Range["A11:E18"].Style.Color = Color.Silver;

            workbook.SaveToFile("sample.xls", ExcelVersion.Version97to2003);
            System.Diagnostics.Process.Start(workbook.FileName);
        }
    }
}

Imports System.Drawing

Imports Spire.Xls

Namespace BackgrandColor
	Class Program
		Private Shared Sub Main(args As String())
			Dim workbook As New Workbook()
			workbook.LoadFromFile("..\..\..\..\Data\country.xls", ExcelVersion.Version97to2003)
			Dim worksheet As Worksheet = workbook.Worksheets(0)

			'set the backgroundcolor=LightBlue of Range["A2:E9"]
			worksheet.Range("A2:E9").Style.Color = Color.LightBlue

			'set the backgroundcolor=Silver of Range["A11:E18"]
			worksheet.Range("A11:E18").Style.Color = Color.Silver

			workbook.SaveToFile("sample.xls", ExcelVersion.Version97to2003)
			System.Diagnostics.Process.Start(workbook.FileName)
		End Sub
	End Class
End Namespace