How to Apply Conditional Formatting to Cells

ByChaknith Bin

May 31, 2025

Updated June 22, 2025

Conditional formatting is a feature in spreadsheet and data processing software that allows you to apply specific formatting styles or rules to cells or data based on certain conditions or criteria. It enables you to visually highlight or emphasize data that meets particular conditions, making it easier to analyze and understand data in a spreadsheet or table.

Easily Add, Retrieve, and Remove Conditional Formatting with IronXL. When adding conditional formatting with styling, you can make font and size adjustments, set borders and alignment, and define background patterns and colors

How to Apply Conditional Formatting to Cells

Download the C# library for conditional formatting
Load an existing Excel spreadsheet or create a new one
Create a conditional formatting rule using the CreateConditionalFormattingRule method
Add the created rule using the AddConditionalFormatting method
Retrieve existing rules using the GetConditionalFormattingAt method

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First Step:

Add Conditional Formatting Example

Conditional formatting consists of rules and styles that are applied when a cell meets the specified rule criteria. The styles can include font and size adjustments, borders and alignment settings, as well as background patterns and colors.

To define a rule, use the CreateConditionalFormattingRule method provided by IronXL. Assign the object returned by this method to a variable, and use it to apply the desired styling. Finally, utilize the AddConditionalFormatting method, providing both the created rule and the cell range to which it should be applied.

:path=/static-assets/excel/content-code-examples/how-to/conditional-formatting-add.cs

using IronXL; using IronXL.Formatting.Enums; // Load an existing Excel workbook WorkBook workBook = WorkBook.Load("sample.xlsx"); // Access the default worksheet within the workbook WorkSheet workSheet = workBook.DefaultWorkSheet; // Create a conditional formatting rule where cells with values less than 8 will have a specific background color // Using a threshold of 8 for the conditional formatting rule var rule = workSheet.ConditionalFormatting.CreateConditionalFormattingRule(ComparisonOperator.LessThan, "8"); // Set style options for the conditional formatting rule // In this case, set the background color to a shade of blue rule.PatternFormatting.BackgroundColor = "#54BDD9"; // Apply the conditional formatting rule to a specific cell range // Here, the rule is applied to the cells in the range A1 to A10 workSheet.ConditionalFormatting.AddConditionalFormatting("A1:A10", rule); // Save the modified workbook to a new file workBook.SaveAs("addConditionalFormatting.xlsx");

Imports IronXL Imports IronXL.Formatting.Enums ' Load an existing Excel workbook Private workBook As WorkBook = WorkBook.Load("sample.xlsx") ' Access the default worksheet within the workbook Private workSheet As WorkSheet = workBook.DefaultWorkSheet ' Create a conditional formatting rule where cells with values less than 8 will have a specific background color ' Using a threshold of 8 for the conditional formatting rule Private rule = workSheet.ConditionalFormatting.CreateConditionalFormattingRule(ComparisonOperator.LessThan, "8") ' Set style options for the conditional formatting rule ' In this case, set the background color to a shade of blue rule.PatternFormatting.BackgroundColor = "#54BDD9" ' Apply the conditional formatting rule to a specific cell range ' Here, the rule is applied to the cells in the range A1 to A10 workSheet.ConditionalFormatting.AddConditionalFormatting("A1:A10", rule) ' Save the modified workbook to a new file workBook.SaveAs("addConditionalFormatting.xlsx")

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Before

After

Below are all the available rules:

NoComparison: The default value.
Between: 'Between' operator
NotBetween: 'Not between' operator
Equal: 'Equal to' operator
NotEqual: 'Not equal to' operator
GreaterThan: 'Greater than' operator
LessThan: 'Less than' operator
GreaterThanOrEqual: 'Greater than or equal to' operator
LessThanOrEqual: 'Less than or equal to' operator

Retrieve Conditional Formatting Example

To retrieve a conditional formatting rule, use the GetConditionalFormattingAt method. The rule object returned may contain multiple rules; use the GetRule method to access a specific one. Most properties of a retrieved rule cannot be modified, yet you can adjust the BackgroundColor via the PatternFormatting property. The following code demonstrates this:

:path=/static-assets/excel/content-code-examples/how-to/conditional-formatting-retrieve.cs

using IronXL; // Load the workbook and select the default worksheet WorkBook workBook = WorkBook.Load("addConditionalFormatting.xlsx"); WorkSheet workSheet = workBook.DefaultWorkSheet; // Check if there are any conditional formatting rules if (workSheet.ConditionalFormatting.Count > 0) { // Retrieve the first conditional formatting rule collection var ruleCollection = workSheet.ConditionalFormatting.GetConditionalFormattingAt(0); // Check if there are any rules in the rule collection if (ruleCollection.GetRuleCount() > 0) { // Retrieve the first rule within the collection var rule = ruleCollection.GetRule(0); // Check if the rule supports pattern formatting before applying changes if (rule.PatternFormatting != null) { // Edit the background color styling of the rule rule.PatternFormatting.BackgroundColor = "#B6CFB6"; } else { Console.WriteLine("Pattern formatting is not supported for this rule."); } } else { Console.WriteLine("No conditional formatting rules found in the rule collection."); } } else { Console.WriteLine("No conditional formatting applied to this worksheet."); } // Save the edited workbook with a new name workBook.SaveAs("editedConditionalFormatting.xlsx");

Imports IronXL ' Load the workbook and select the default worksheet Private workBook As WorkBook = WorkBook.Load("addConditionalFormatting.xlsx") Private workSheet As WorkSheet = workBook.DefaultWorkSheet ' Check if there are any conditional formatting rules If workSheet.ConditionalFormatting.Count > 0 Then	' Retrieve the first conditional formatting rule collection	Dim ruleCollection = workSheet.ConditionalFormatting.GetConditionalFormattingAt(0)	' Check if there are any rules in the rule collection	If ruleCollection.GetRuleCount() > 0 Then	' Retrieve the first rule within the collection	Dim rule = ruleCollection.GetRule(0)	' Check if the rule supports pattern formatting before applying changes	If rule.PatternFormatting IsNot Nothing Then	' Edit the background color styling of the rule	rule.PatternFormatting.BackgroundColor = "#B6CFB6"	Else	Console.WriteLine("Pattern formatting is not supported for this rule.")	End If	Else	Console.WriteLine("No conditional formatting rules found in the rule collection.")	End If Else	Console.WriteLine("No conditional formatting applied to this worksheet.") End If ' Save the edited workbook with a new name workBook.SaveAs("editedConditionalFormatting.xlsx")

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Remove Conditional Formatting Example

To remove a conditional formatting rule, use the RemoveConditionalFormatting method. Pass the index of the targeted rule to this method.

:path=/static-assets/excel/content-code-examples/how-to/conditional-formatting-remove.cs

using IronXL; // Load an Excel workbook from the specified file path WorkBook workBook = WorkBook.Load("addConditionalFormatting.xlsx"); // Select the default worksheet from the loaded workbook WorkSheet workSheet = workBook.DefaultWorkSheet; // Check if there is at least one conditional formatting rule to remove // Attempting to remove a rule when none exist will throw an error. if (workSheet.ConditionalFormatting.Count > 0) { // Remove the first conditional formatting rule from the default worksheet // Index 0 indicates the first conditional formatting rule applied to the worksheet workSheet.ConditionalFormatting.Remove(0); } // Save the updated workbook to a new file with the specified file name workBook.SaveAs("removedConditionalFormatting.xlsx");

Imports IronXL ' Load an Excel workbook from the specified file path Private workBook As WorkBook = WorkBook.Load("addConditionalFormatting.xlsx") ' Select the default worksheet from the loaded workbook Private workSheet As WorkSheet = workBook.DefaultWorkSheet ' Check if there is at least one conditional formatting rule to remove ' Attempting to remove a rule when none exist will throw an error. If workSheet.ConditionalFormatting.Count > 0 Then	' Remove the first conditional formatting rule from the default worksheet	' Index 0 indicates the first conditional formatting rule applied to the worksheet	workSheet.ConditionalFormatting.Remove(0) End If ' Save the updated workbook to a new file with the specified file name workBook.SaveAs("removedConditionalFormatting.xlsx")

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Frequently Asked Questions

What is conditional formatting?

Conditional formatting is a feature in spreadsheet and data processing software that allows you to apply specific formatting styles or rules to cells or data based on certain conditions or criteria. It helps in visually highlighting or emphasizing data that meets particular conditions.

How can I apply conditional formatting using IronXL?

To apply conditional formatting using IronXL, you need to create a rule using the `CreateConditionalFormattingRule` method, apply the desired styles, and then add the rule to a specific cell range using the `AddConditionalFormatting` method.

What are the available conditional formatting operators in IronXL?

IronXL provides several operators for conditional formatting including: NoComparison, Between, NotBetween, Equal, NotEqual, GreaterThan, LessThan, GreaterThanOrEqual, and LessThanOrEqual.

How can I retrieve an existing conditional formatting rule in IronXL?

To retrieve an existing conditional formatting rule, use the `GetConditionalFormattingAt` method. This method returns an object containing multiple rules, which you can access using the `GetRule` method.

Is it possible to modify properties of a retrieved conditional formatting rule?

Most properties of a retrieved conditional formatting rule cannot be modified; however, you can adjust the **BackgroundColor** through the **PatternFormatting** property.

How do I remove a conditional formatting rule using IronXL?

To remove a conditional formatting rule, use the `RemoveConditionalFormatting` method and pass the index of the rule you wish to remove.

Can I apply styling like font and size adjustments with conditional formatting in IronXL?

Yes, with IronXL, you can apply various styles such as font and size adjustments, borders, alignment settings, and background patterns and colors as part of conditional formatting rules.

What is the first step to apply conditional formatting using IronXL?

The first step is to download the IronXL.Excel library from NuGet, which provides the necessary methods to apply conditional formatting in Excel spreadsheets.

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Software Engineer

Chaknith is the Sherlock Holmes of developers. It first occurred to him he might have a future in software engineering, when he was doing code challenges for fun. His focus is on IronXL and IronBarcode, but he takes pride in helping customers with every product. Chaknith leverages his knowledge from talking directly with customers, to help further improve the products themselves. His anecdotal feedback goes beyond Jira tickets and supports product development, documentation and marketing, to improve customer’s overall experience.When he isn’t in the office, he can be found learning about machine learning, coding and hiking.