To add a comment to a cell, complete the following steps:

1. Add a reference to C1.WPF.Excel.dll and create a C1XLBook.

   <// Create a new workbook C1XLBook book = new C1XLBook();

2. Add text to a cell in the worksheet using the following code:

   book.Sheets[0][2, 3].Value = "test";

3. Add a comment to the XLCommentCollection and create a box to show it in using the following code:

   book.Sheets[0].Comments.Add(2, 3, "John", "Test comment");
book.Sheets[0].Comments[0].TextBox.Rectangle = new Rect(220, 210, 1900, 1200);

4. Save and open the book:

   C#	Copy Code
   // Save and open the file book.Save(@"C:\test.xlsx"); System.Diagnostics.Process.Start(@"C:\test.xlsx");

5. Run the program. The spreadsheet will open and look similar to the following: