How to compare cell values in Excel using C#, VB.NET?

Syncfusion Excel (XlsIO) library is a .NET Excel library used to create, read, and edit Excel documents. It also converts Excel documents to PDF files.

This article explains how to compare cell values in Excel using C# and VB.NET.

Include the following namespace in the Program.cs file.

C#

using Syncfusion.XlsIO;

VB.NET

Imports Syncfusion.XlsIO

Use the following code snippet for comparing cell values in Excel.

C#

using (ExcelEngine excelEngine = new ExcelEngine())
{
    IApplication application = excelEngine.Excel;
    application.DefaultVersion = ExcelVersion.Xlsx;
    FileStream inputStream = new FileStream("Data/Input.xlsx", FileMode.Open, FileAccess.Read);
    IWorkbook workbook = application.Workbooks.Open(inputStream);
    IWorksheet worksheet = workbook.Worksheets[0];
    IRange usedRange = worksheet.UsedRange;

    // Loop through rows (starting from row 2 to skip header if needed)
    for (int row = 2; row <= usedRange.LastRow; row++)
    {
        // Compare values between column 1 and column 2
        if (worksheet.UsedRange[row, 1].Value != worksheet.UsedRange[row, 2].Value && !worksheet.UsedRange[row, 2].IsBlank)
        {
            // Highlight mismatched cells with red color
            worksheet.UsedRange[row, 2].CellStyle.ColorIndex = ExcelKnownColors.Red;
        }
    }

    #region Save
    // Saving the workbook
    FileStream outputStream = new FileStream(Path.GetFullPath("Output/Output.xlsx"), FileMode.Create, FileAccess.Write);
    workbook.SaveAs(outputStream);
    #endregion

    // Dispose streams
    outputStream.Dispose();
    inputStream.Dispose();
}

VB.NET

Using excelEngine As New ExcelEngine()
    Dim application As IApplication = excelEngine.Excel
    application.DefaultVersion = ExcelVersion.Xlsx
    Dim workbook As IWorkbook = application.Workbooks.Open("Input.xlsx")
    Dim worksheet As IWorksheet = workbook.Worksheets(0)
    Dim usedRange As IRange = worksheet.UsedRange

    ' Loop through rows (starting from row 2 to skip header if needed)
    For row As Integer = 2 To usedRange.LastRow
        Dim value1 As String = worksheet.UsedRange(row, 1).Value
        Dim value2 As String = worksheet.UsedRange(row, 2).Value

        ' Compare values between column 1 and column 2
        If value1 <> value2 AndAlso Not worksheet.UsedRange(row, 2).IsBlank Then
            ' Highlight mismatched cells with red color
            worksheet.UsedRange(row, 2).CellStyle.ColorIndex = ExcelKnownColors.Red
        End If
    Next

    ' Saving the workbook
    workbook.SaveAs("Output.xlsx")
End Using

You can get the complete sample for comparing cell values in Excel from the below link :

I hope you enjoyed learning about how to compare cell values in Excel using C# and VB.NET in XlsIO.

Take a moment to peruse the documentation where you can find basic Excel document processing options along with features like import and export data, charts, formulas, conditional formatting, data validation, tables, pivot tables, and protect Excel documents, as well as the PDF, CSV, and Image conversions with code examples.
You can refer to our XIsIO’s feature tour page to learn about its other groundbreaking features. Explore our UG documentation and online demos to understand how to manipulate data in Excel documents.

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