UG documentation 1024021: FAQ for How to reorder conditional formats based on internal priority value?

Document-Processing/Excel/Excel-Library/NET/faqs/how-to-reorder-conditional-formats-based-on-priority.md

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+---
+title: Reorder conditional formats by priority value | Syncfusion
+description: This page explains reordering conditional formatting rules in XlsIO using the internal Priority attribute to match Microsoft Excel behavior consistently.
+platform: document-processing
+control: XlsIO
+documentation: UG
+---
+
+# How to reorder conditional formats based on priority value?
+
+In Microsoft Excel, when multiple conditional formatting rules are applied to a range, the rules are serialized sequentially in the sheet.xml file. However, this serialization order does not represent the actual evaluation order. Excel determines the correct rule processing sequence using the **Priority** attribute defined for each conditional formatting rule.
+
+XlsIO parses conditional formatting rules in the same order in which they are serialized in the Excel file. This behavior aligns with the sheet.xml data structure but does not reflect Excel's rule evaluation order, which is based on priority.
+
+To achieve consistency with Excel's behavior, use the `GetSortedConditionalFormats` helper method that reorders conditional formatting rules based on their internal Priority value using reflection.
+
+The following code example demonstrates how to retrieve and sort conditional formats by priority.
+
+{% tabs %}
+{% highlight c# tabtitle="C# [Cross-platform]" %}
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using Syncfusion.XlsIO;
+using Syncfusion.XlsIO.Implementation;
+
+class Program
+{
+    static void Main(string[] args)
+    {
+        using (ExcelEngine excelEngine = new ExcelEngine())
+        {
+            // Instantiate the Excel application object
+            IApplication application = excelEngine.Excel;
+
+            // Assign default application version
+            application.DefaultVersion = ExcelVersion.Xlsx;
+
+            // Open a workbook with conditional formatting applied
+            IWorkbook workbook = application.Workbooks.Open(Path.GetFullPath(@"Data/InputTemplate.xlsx"));
+
+            // Access first worksheet from the workbook
+            IWorksheet worksheet = workbook.Worksheets[0];
+
+            // Get conditional formats from cell B3
+            IConditionalFormats conditionalFormats = worksheet["B3"].ConditionalFormats;
+
+            // Get sorted conditional formats based on internal Priority
+            List<ConditionalFormatImpl> sortedFormats = GetSortedConditionalFormats(conditionalFormats);
+
+            // Display the formula from each conditional format in priority order
+            for (int i = 0; i < sortedFormats.Count; i++)
+            {
+                IConditionalFormat format = sortedFormats[i];
+                Console.WriteLine(format.FirstFormula);
+            }
+
+            // Save the workbook
+            workbook.SaveAs(Path.GetFullPath(@"Output/Output.xlsx"));
+        }
+    }
+
+    /// <summary>
+    /// Retrieves conditional format implementations sorted by their internal Priority value.
+    /// This ensures the formats are processed in the same order as Microsoft Excel.
+    /// </summary>
+    /// <param name="conditionalFormats">The conditional formats collection from XlsIO.</param>
+    /// <returns>A list of ConditionalFormatImpl sorted by priority.</returns>
+    static List<ConditionalFormatImpl> GetSortedConditionalFormats(IConditionalFormats conditionalFormats)
+    {
+        List<ConditionalFormatImpl> result = new List<ConditionalFormatImpl>();
+
+        // Use reflection to access the internal GetCondition method and Priority property
+        MethodInfo getConditionMethod = typeof(ConditionalFormatWrapper).GetMethod("GetCondition", BindingFlags.Instance | BindingFlags.NonPublic);
+        PropertyInfo priorityProp = typeof(ConditionalFormatImpl).GetProperty("Priority", BindingFlags.Instance | BindingFlags.NonPublic);
+
+        // Iterate through each conditional format in the collection
+        for (int i = 0; i < conditionalFormats.Count; i++)
+        {
+            IConditionalFormat format = conditionalFormats[i];
+            ConditionalFormatImpl impl = format as ConditionalFormatImpl;
+
+            // If format is a wrapper type, invoke GetCondition to get the underlying implementation
+            if (impl == null && format is ConditionalFormatWrapper wrapper)
+            {
+                impl = getConditionMethod.Invoke(wrapper, null) as ConditionalFormatImpl;
+            }
+
+            if (impl != null)
+            {
+                result.Add(impl);
+            }
+        }
+
+        // Sort by Priority value to match Excel's evaluation order
+        return result.OrderBy(f => (int)priorityProp.GetValue(f)).ToList();
+    }
+}
+{% endhighlight %}
+
+{% highlight c# tabtitle="C# [Windows-specific]" %}
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using Syncfusion.XlsIO;
+using Syncfusion.XlsIO.Implementation;
+
+class Program
+{
+    static void Main(string[] args)
+    {
+        using (ExcelEngine excelEngine = new ExcelEngine())
+        {
+            // Instantiate the Excel application object
+            IApplication application = excelEngine.Excel;
+
+            // Assign default application version
+            application.DefaultVersion = ExcelVersion.Xlsx;
+
+            // Open a workbook with conditional formatting applied
+            IWorkbook workbook = application.Workbooks.Open("InputTemplate.xlsx");
+
+            // Access first worksheet from the workbook
+            IWorksheet worksheet = workbook.Worksheets[0];
+
+            // Get conditional formats from cell B3
+            IConditionalFormats conditionalFormats = worksheet["B3"].ConditionalFormats;
+
+            // Get sorted conditional formats based on internal Priority
+            List<ConditionalFormatImpl> sortedFormats = GetSortedConditionalFormats(conditionalFormats);
+
+            // Display the formula from each conditional format in priority order
+            for (int i = 0; i < sortedFormats.Count; i++)
+            {
+                IConditionalFormat format = sortedFormats[i];
+                Console.WriteLine(format.FirstFormula);
+            }
+
+            // Save the workbook
+            workbook.SaveAs("Output.xlsx");
+        }
+    }
+
+    /// <summary>
+    /// Retrieves conditional format implementations sorted by their internal Priority value.
+    /// This ensures the formats are processed in the same order as Microsoft Excel.
+    /// </summary>
+    /// <param name="conditionalFormats">The conditional formats collection from XlsIO.</param>
+    /// <returns>A list of ConditionalFormatImpl sorted by priority.</returns>
+    static List<ConditionalFormatImpl> GetSortedConditionalFormats(IConditionalFormats conditionalFormats)
+    {
+        List<ConditionalFormatImpl> result = new List<ConditionalFormatImpl>();
+
+        // Use reflection to access the internal GetCondition method and Priority property
+        MethodInfo getConditionMethod = typeof(ConditionalFormatWrapper).GetMethod("GetCondition", BindingFlags.Instance | BindingFlags.NonPublic);
+        PropertyInfo priorityProp = typeof(ConditionalFormatImpl).GetProperty("Priority", BindingFlags.Instance | BindingFlags.NonPublic);
+
+        // Iterate through each conditional format in the collection
+        for (int i = 0; i < conditionalFormats.Count; i++)
+        {
+            IConditionalFormat format = conditionalFormats[i];
+            ConditionalFormatImpl impl = format as ConditionalFormatImpl;
+
+            // If format is a wrapper type, invoke GetCondition to get the underlying implementation
+            if (impl == null && format is ConditionalFormatWrapper wrapper)
+            {
+                impl = getConditionMethod.Invoke(wrapper, null) as ConditionalFormatImpl;
+            }
+
+            if (impl != null)
+            {
+                result.Add(impl);
+            }
+        }
+
+        // Sort by Priority value to match Excel's evaluation order
+        return result.OrderBy(f => (int)priorityProp.GetValue(f)).ToList();
+    }
+}
+{% endhighlight %}
+
+{% highlight vb.net tabtitle="VB.NET [Windows-specific]" %}
+Imports System
+Imports System.Collections.Generic
+Imports System.Linq
+Imports System.Reflection
+Imports Syncfusion.XlsIO
+
+Module Program
+    Sub Main(args As String())
+        Using excelEngine As New ExcelEngine()
+            ' Instantiate the Excel application object
+            Dim application As IApplication = excelEngine.Excel
+
+            ' Assign default application version
+            application.DefaultVersion = ExcelVersion.Xlsx
+
+            ' Open a workbook with conditional formatting applied
+            Dim workbook As IWorkbook = application.Workbooks.Open("InputTemplate.xlsx")
+
+            ' Access first worksheet from the workbook
+            Dim worksheet As IWorksheet = workbook.Worksheets(0)
+
+            ' Get conditional formats from cell B3
+            Dim conditionalFormats As IConditionalFormats = worksheet("B3").ConditionalFormats
+
+            ' Get sorted conditional formats based on internal Priority
+            Dim sortedFormats As List(Of ConditionalFormatImpl) = GetSortedConditionalFormats(conditionalFormats)
+
+            ' Display the formula from each conditional format in priority order
+            For i As Integer = 0 To sortedFormats.Count - 1
+                Dim format As IConditionalFormat = sortedFormats(i)
+                Console.WriteLine(format.FirstFormula)
+            Next
+
+            ' Save the workbook
+            workbook.SaveAs("Output.xlsx")
+        End Using
+    End Sub
+
+    ''' <summary>
+    ''' Retrieves conditional format implementations sorted by their internal Priority value.
+    ''' This ensures the formats are processed in the same order as Microsoft Excel.
+    ''' </summary>
+    ''' <param name="conditionalFormats">The conditional formats collection from XlsIO.</param>
+    ''' <returns>A list of ConditionalFormatImpl sorted by priority.</returns>
+    Function GetSortedConditionalFormats(conditionalFormats As IConditionalFormats) As List(Of ConditionalFormatImpl)
+        Dim result As New List(Of ConditionalFormatImpl)()
+
+        ' Use reflection to access the internal GetCondition method and Priority property
+        Dim getConditionMethod As MethodInfo = GetType(ConditionalFormatWrapper).GetMethod("GetCondition", BindingFlags.Instance Or BindingFlags.NonPublic)
+        Dim priorityProp As PropertyInfo = GetType(ConditionalFormatImpl).GetProperty("Priority", BindingFlags.Instance Or BindingFlags.NonPublic)
+
+        ' Iterate through each conditional format in the collection
+        For i As Integer = 0 To conditionalFormats.Count - 1
+            Dim format As IConditionalFormat = conditionalFormats(i)
+            Dim impl As ConditionalFormatImpl = TryCast(format, ConditionalFormatImpl)
+
+            ' If format is a wrapper type, invoke GetCondition to get the underlying implementation
+            If impl Is Nothing AndAlso TypeOf format Is ConditionalFormatWrapper Then
+                Dim wrapper As ConditionalFormatWrapper = DirectCast(format, ConditionalFormatWrapper)
+                impl = TryCast(getConditionMethod.Invoke(wrapper, Nothing), ConditionalFormatImpl)
+            End If
+
+            If impl IsNot Nothing Then
+                result.Add(impl)
+            End If
+        Next
+
+        ' Sort by Priority value to match Excel's evaluation order
+        Return result.OrderBy(Function(f) CInt(priorityProp.GetValue(f))).ToList()
+    End Function
+End Module
+{% endhighlight %}
+{% endtabs %}