Add comment

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;

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

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

            //Define a range object(A1)
            Excel.Range range = sheet.Range["A1", "A1"];
            range.Value = "Spire.XLS";

            //Add a comment to the range
            Excel.Comment comment = range.AddComment("Spire.XLS for .NET");

            //Set the format of the comment                     
            comment.Shape.Width = 200;
            comment.Shape.Height = 50;    
        
            //Save the file
            workbook.SaveAs("Comment.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();

            //Define a range object(A1)
            Worksheet sheet = workbook.Worksheets[0];
            CellRange range = sheet.Range["A1:A1"];
            range.Text = "Spire.XLS";

            //Add a comment
            ExcelComment comment = range.AddComment();
            comment.RichText.Text = "Spire.XLS for .NET";

            //Set the format of the comment          
            comment.Width = 200;
            comment.Height = 50;
            
            //Save and Launch
            workbook.SaveToFile("Comment.xlsx",ExcelVersion.Version2013);
            System.Diagnostics.Process.Start("Comment.xlsx");         
        }
    }
}

AddComment.zip