using System;
using System.Collections.Generic;
using System.Text;
using System.Diagnostics;
using Bytescout.Spreadsheet;

namespace HelloWorld
{
class Program
{
static void Main(string[] args)
{
// Create new Spreadsheet
Spreadsheet document = new Spreadsheet("Data.xls");

// Get worksheet by name
Worksheet worksheet = document.Workbook.Worksheets.ByName("Sample");

// Spellcheck words
for (int i = 0; i < 5; i++)
{
// Set current cell
Cell currentCell = worksheet.Cell(0, i);

// Spellcheck current cell
if ((string)currentCell.Value == "Simpsan")
{
// Set fill pattern
currentCell.FillPattern = Bytescout Spreadsheet.Constants.PatternStyle.Solid;

// Markup wrong word by red color
currentCell.FillPatternForeColor = System.Drawing.Color.Red;
}
}

// Save document
document.SaveAs("CheckedData.xls");

// Close document
document.Close();

// open generated XLS document in default program
Process.Start("CheckedData.xls");
}
}
}

Download example source code: bytescoutxls_validate_cells_mark_wrong_with_color.zip (8 KB)