Set cell style in Excel

VSTO
Spire.XLS
Download Sample Code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Xml.Linq;
using Excel = Microsoft.Office.Interop.Excel;
using Office = Microsoft.Office.Core;
using Microsoft.Office.Tools.Excel;
using System.Drawing;
using System.Reflection;

namespace VSTO
{
    public partial class ThisAddIn
    {
        private void ThisAddIn_Startup(object sender, System.EventArgs e)
        {
            //Open the workbook file
            Excel.Workbook workbook = this.Application.Workbooks.Add();

            //Get the active sheet
            Excel.Worksheet sheet = workbook.ActiveSheet;

            //Add style of specified range           
            Excel.Style style = workbook.Styles.Add("Style");
            style.Font.Size = 16;
            style.Font.Color = Color.Red;
            style.Interior.Color = Color.Black;
            style.Interior.Pattern = Excel.XlPattern.xlPatternSolid;
            Excel.Range range = sheet.get_Range("A1","A7");
            range.Value = "Spire";
            range.Style = "Style";

            //Save the file
            workbook.SaveAs("StyleExcel.xlsx");
        }

        private void ThisAddIn_Shutdown(object sender, System.EventArgs e)
        {
        }

        #region VSTO generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InternalStartup()
        {
            this.Startup += new System.EventHandler(ThisAddIn_Startup);
            this.Shutdown += new System.EventHandler(ThisAddIn_Shutdown);
        }
        
        #endregion
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Spire.Xls;
using System.Drawing;

namespace Spire.XLS
{
    class Program
    {
        static void Main(string[] args)
        {
            //Initialize a new instance of workbook
            Workbook workbook = new Workbook();

            //Get the first worksheet
            Worksheet sheet = workbook.Worksheets[0];
            
            //Add style of specified range
            CellStyle style=workbook.Styles.Add("Style");
            CellRange range = sheet.Range["A1:A7"];
            range.Text = "Spire";
            range.Style.Font.Size = 16;
            range.Style.Font.Color = Color.Red;
            range.Style.Interior.Color = Color.Black;
            range.Style.Interior.FillPattern = ExcelPatternType.Solid;

            //Save and Launch
            workbook.SaveToFile("StyleExcel.xlsx", ExcelVersion.Version2010);
            System.Diagnostics.Process.Start("StyleExcel.xlsx");

        }
    }
}

SetCellStyle.zip