From 6cd77bcc73bdc7773b931b9ab68d61a3b6d10dbd Mon Sep 17 00:00:00 2001
From: KarthikaSF4773 <karthika.santhanakrishnan@syncfusion.com>
Date: Mon, 15 Dec 2025 18:08:54 +0530
Subject: [PATCH] 990897-NumberFormatColumnDev

---
 ...formatting-to-an-entire-column-in-Excel.md | 83 +++++++++++++++++++
 1 file changed, 83 insertions(+)
 create mode 100644 Document-Processing/Excel/Excel-Library/NET/faqs/how-to-apply-number-formatting-to-an-entire-column-in-Excel.md

diff --git a/Document-Processing/Excel/Excel-Library/NET/faqs/how-to-apply-number-formatting-to-an-entire-column-in-Excel.md b/Document-Processing/Excel/Excel-Library/NET/faqs/how-to-apply-number-formatting-to-an-entire-column-in-Excel.md
new file mode 100644
index 000000000..8efd2b13b
--- /dev/null
+++ b/Document-Processing/Excel/Excel-Library/NET/faqs/how-to-apply-number-formatting-to-an-entire-column-in-Excel.md
@@ -0,0 +1,83 @@
+---
+title: Apply number formatting to an entire column in Excel | Syncfusion
+description: Code example to apply number formatting to an entire column in Excel using Syncfusion .NET Excel library (XlsIO).
+platform: document-processing
+control: XlsIO
+documentation: UG
+---
+
+# How to apply number formatting to an entire column in Excel?
+
+The following code examples demonstrate applying number formatting to an entire column in Excel using C# (Cross-platform and Windows-specific) and VB.NET.
+
+{% tabs %}   
+{% highlight c# tabtitle="C# [Cross-platform]" playgroundButtonLink="https://raw.githubusercontent.com/SyncfusionExamples/XlsIO-Examples/master/FAQ/Column%20Number%20Format/.NET/ColumnNumberFormat/ColumnNumberFormat/Program.cs,180" %}
+using (ExcelEngine excelEngine = new ExcelEngine())
+{
+    IApplication application = excelEngine.Excel;
+    application.DefaultVersion = ExcelVersion.Xlsx;
+    IWorkbook workbook = application.Workbooks.Open(Path.GetFullPath(@"Data/Input.xlsx"));
+    IWorksheet sheet = workbook.Worksheets[0];
+
+    //Case 1: Apply direct number format (zero-based index)
+    sheet.Columns[0].NumberFormat = "yyyy-mm-dd"; //Column A
+    sheet.Columns[3].NumberFormat = "$#,##0.00"; //Column D
+    sheet.Columns[4].NumberFormat = "0.00%"; //Column E
+
+    //Case 2: Apply style-based format (one-based index)
+    IStyle style = workbook.Styles.Add("DecimalStyle");
+    style.NumberFormat = "0.00";
+    sheet.SetDefaultColumnStyle(3, style); //Column C 
+
+    //Saving the workbook
+    workbook.SaveAs(Path.GetFullPath(@"Output/Output.xlsx"));
+}
+{% endhighlight %}
+
+{% highlight c# tabtitle="C# [Windows-specific]" %} 
+using (ExcelEngine excelEngine = new ExcelEngine())
+{
+    IApplication application = excelEngine.Excel;
+    application.DefaultVersion = ExcelVersion.Xlsx;
+    IWorkbook workbook = application.Workbooks.Open("Input.xlsx");
+    IWorksheet sheet = workbook.Worksheets[0];
+
+    //Case 1: Apply direct number format (zero-based index)
+    sheet.Columns[0].NumberFormat = "yyyy-mm-dd"; //Column A
+    sheet.Columns[3].NumberFormat = "$#,##0.00"; //Column D
+    sheet.Columns[4].NumberFormat = "0.00%"; //Column E
+
+    //Case 2: Apply style-based format (one-based index)
+    IStyle style = workbook.Styles.Add("DecimalStyle");
+    style.NumberFormat = "0.00";
+    sheet.SetDefaultColumnStyle(3, style); //Column C 
+
+    //Saving the workbook
+    workbook.SaveAs("Output.xlsx");
+}
+{% endhighlight %}
+
+{% highlight vb.net tabtitle="VB.NET [Windows-specific]" %}
+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 sheet As IWorksheet = workbook.Worksheets(0)
+
+    'Case 1: Apply direct number format (zero-based index)
+    sheet.Columns(0).NumberFormat = "yyyy-mm-dd" 'Column A
+    sheet.Columns(3).NumberFormat = "$#,##0.00" 'Column D
+    sheet.Columns(4).NumberFormat = "0.00%" 'Column E
+
+    'Case 2: Apply style-based format (one-based index)
+    Dim style As IStyle = workbook.Styles.Add("DecimalStyle")
+    style.NumberFormat = "0.00"
+    sheet.SetDefaultColumnStyle(3, style) 'Column C
+
+    'Save the workbook
+    workbook.SaveAs("Output.xlsx")
+End Using
+{% endhighlight %}
+{% endtabs %}       
+ 
+A complete working example that shows how to apply number formatting to an entire column in Excel using C# is present on <a href="https://github.com/SyncfusionExamples/XlsIO-Examples/tree/master/FAQ/Column%20Number%20Format/.NET/ColumnNumberFormat">this GitHub page</a>.
\ No newline at end of file