GemBox.Spreadsheet is a .NET component that enables you to read, write, edit, convert, and print spreadsheet files from your .NET applications using one simple API.

ExcelCell Comments

Following example demonstrates how to set Excel cell comment with location, text and visibility.

Sample also shows how to format individual characters and words within a comment text.

Comments reading/writing is supported in XLSX and ODS file formats.

Comments formatting is supported only in XLSX.

Screenshot
ExcelCell Comments Screenshot

See the full code below, use Run Example to execute. 

using GemBox.Spreadsheet;
using System;
using System.IO;

class Sample
{
    [STAThread]
    static void Main(string[] args)
    {
        // If using Professional version, put your serial key below.
        SpreadsheetInfo.SetLicense("FREE-LIMITED-KEY");

        ExcelFile ef = new ExcelFile();
        ExcelWorksheet ws = ef.Worksheets.Add("Comments");

        ws.Cells[0, 0].Value = "Comment examples:";

        ws.Cells[2, 1].Comment.Text = "Empty cell.";

        ws.Cells[4, 1].Value = 5;
        ws.Cells[4, 1].Comment.Text = "Cell with a number.";

        ws.Cells["B7"].Value = "Cell B7";

        ExcelComment comment = ws.Cells["B7"].Comment;
        comment.Text = "Some formatted text.\nComment is:\na) multiline,\nb) large,\nc) visible, and \nd) formatted.";
        comment.IsVisible = true;
        comment.TopLeftCell = new AnchorCell(ws.Columns[3], ws.Rows[4], true);
        comment.BottomRightCell = new AnchorCell(ws.Columns[5], ws.Rows[10], false);

        // Get first 20 characters of a string
        FormattedCharacterRange characters = comment.GetCharacters(0, 20);

        // Apply color, italic and size to selected characters
        characters.Font.Color = SpreadsheetColor.FromName(ColorName.Orange);
        characters.Font.Italic = true;
        characters.Font.Size = 300;

        // Apply color to 'formatted' part of text
        comment.GetCharacters(5, 9).Font.Color = SpreadsheetColor.FromName(ColorName.Red);

        ef.Save("Comments.xlsx");
    }
}
Imports GemBox.Spreadsheet
Imports System.IO

Module Samples

    Sub Main()

        ' If using Professional version, put your serial key below.
        SpreadsheetInfo.SetLicense("FREE-LIMITED-KEY")

        Dim ef As ExcelFile = New ExcelFile
        Dim ws As ExcelWorksheet = ef.Worksheets.Add("Comments")

        ws.Cells.Item(0, 0).Value = "Comment examples:"

        ws.Cells.Item(2, 1).Comment.Text = "Empty cell."

        ws.Cells.Item(4, 1).Value = 5
        ws.Cells.Item(4, 1).Comment.Text = "Cell with a number."

        ws.Cells.Item("B7").Value = "Cell B7"

        Dim comment As ExcelComment = ws.Cells("B7").Comment
        comment.Text = "Some formatted text. Comment is:" & ChrW(10) & "a) multiline," & ChrW(10) & "b) large," & ChrW(10) & "c) visible, and " & ChrW(10) & "d) formatted."
        comment.IsVisible = True
        comment.TopLeftCell = New AnchorCell(ws.Columns(3), ws.Rows(4), True)
        comment.BottomRightCell = New AnchorCell(ws.Columns(5), ws.Rows(10), False)

        ' Get first 20 characters of a string
        Dim characters As FormattedCharacterRange = comment.GetCharacters(0, 20)

        ' Apply color, italic and size to selected characters
        characters.Font.Color = SpreadsheetColor.FromName(ColorName.Orange)
        characters.Font.Italic = True
        characters.Font.Size = 300

        ' Apply color to 'formatted' part of text
        comment.GetCharacters(5, 9).Font.Color = SpreadsheetColor.FromName(ColorName.Red)

        ef.Save("Comments.xlsx")

    End Sub

End Module

Check next sample.