How to create conditional formatting in C#.NET

EasyXLS Excel library can be used to export Excel files in C#. The library works with .NET Framework or .NET Core platform.

Step 1: Download EasyXLS Excel Library for .NET

To download the trial version of EasyXLS Excel Library, press the below button:

Download EasyXLS™ Excel Library for C#

If you already own a license key, you may login and download EasyXLS from your account.

Install the downloaded EasyXLS installer for v8.6 or earlier.

Step 2: License file setup

Step required for EasyXLS v9.0 or later.

If you are using a trial, generate a trial license file from EasyXLS trials page. The trial license is valid for 30-days.

If you own a license key, you may login to the account that purchased the license and generate the license file from:

Setup the license file into your project using these guidelines.

Step 3: Create a C# project

If don't have a project, create one as ASP.NET web application, windows forms app, console application, class library or service.

Step 4: Include EasyXLS library into project

EasyXLS.dll must be added as reference to your project. EasyXLS.dll can be found:
- Inside the downloaded archive at Step 1 for EasyXLS v9.0 or later
- Under installation path for EasyXLS v8.6 or earlier, in "Dot NET version" folder.

Add EasyXLS reference

Step 5: Run C# code that creates conditional formatting in Excel cells

Execute the following C# code that exports an Excel file and sets conditional formatting to a range. The first step is to set the range where the conditional formatting will be applied, then set the formatting options.

/* ------------------------------------------------------------
 * Tutorial 14
 * This tutorial shows how to create an Excel file in C# having
 * a sheet and conditional formatting for cell ranges.
 * --------------------------------------------------------- */

using System;
using EasyXLS;
using EasyXLS.Constants;
using System.Drawing;

public class Tutorial14
    static void Main()
        Console.WriteLine("Tutorial 14\n-----------\n");

        // Create an instance of the class that exports Excel files having one sheet
        ExcelDocument workbook = new ExcelDocument(1);

        // Get the table of data for the first worksheet
        ExcelWorksheet xlsTab = ((ExcelWorksheet)workbook.easy_getSheet("Sheet1"));
        ExcelTable xlsTable = xlsTab.easy_getExcelTable();

        // Add data in cells 
        for (int i=0;i<6;i++)
            for (int j=0;j<4;j++)
                    xlsTable.easy_getCell(i, j).setValue("12");
                else if((j==2)&&(i<2))
                    xlsTable.easy_getCell(i, j).setValue("1000");
                    xlsTable.easy_getCell(i, j).setValue("9");
                xlsTable.easy_getCell(i, j).setDataType(DataType.NUMERIC);

        // Set conditional formatting
        xlsTab.easy_addConditionalFormatting("A1:C3", ConditionalFormatting.OPERATOR_BETWEEN, 
                                                            "=9", "=11", true, true, Color.Red);

        // Set another conditional formatting
        xlsTab.easy_addConditionalFormatting("A6:C6", ConditionalFormatting.OPERATOR_BETWEEN, 
                                                                "=COS(PI())+2", "", Color.Bisque);

        // Export Excel file
        Console.WriteLine("Writing file C:\\Samples\\Tutorial14 - conditional formatting in Excel.xlsx.");
        workbook.easy_WriteXLSXFile("C:\\Samples\\Tutorial14 - conditional formatting in Excel.xlsx");

        // Confirm export of Excel file
        String sError = workbook.easy_getError();
        if (sError.Equals(""))
            Console.Write("\nFile successfully created. Press Enter to Exit...");
            Console.Write("\nError encountered: " + sError + "\nPress Enter to Exit...");

        // Dispose memory


EasyXLS Excel libraries:

Excel Library for C#
full .NET version to import, export or convert Excel files
Excel Writer for C#
.NET version to create and export Excel files
Download EasyXLS™ Excel Library for C#

File formats:

MS Excel 97 - 2003
MS Excel 2007 - 2019
MS Excel 2021
Office 365