How to protect certain cells in C#, VB.NET and WinForms Excel?

Syncfusion Excel (XlsIO) library is a .NET Excel library used to create, read, and edit Excel documents. Using this library, you can protect certain cells in C# and VB.NET.  

All cells in an Excel spreadsheet have a "Locked" property which determines if the cell will be editable when the worksheet is protected. All the cells are set to locked by default, so when a worksheet is protected all the cells in the worksheet get protected by default. However, there is often a need to protect certain cells only in a worksheet, in this scenario, we would need to protect a worksheet and set the IsLocked property to false for the cells that you want the end user to edit even when the worksheet is protected.

Steps to protect certain cells programmatically:

Step 1: Create a new C# console application project.

Create a new C# console application

Step 2: Install Syncfusion.XlsIO.WinForms NuGet package as a reference to your .NET Framework applications from the NuGet.org.

Install NuGet package

Step 3: Include the following namespace in the Program.cs file.

C#

using Syncfusion.XlsIO;

VB.NET

Imports Syncfusion.XlsIO

Step 4: Use the following code snippet to create Excel file with simple text.

C#

//Create an instance of ExcelEngine
using (ExcelEngine excelEngine = new ExcelEngine())
{
  //Set the default application version as Excel 2016
  excelEngine.Excel.DefaultVersion = ExcelVersion.Excel2016;
 
  //Create a workbook with a worksheet
  IWorkbook workbook = excelEngine.Excel.Workbooks.Create(1);
 
  //Access first worksheet from the workbook instance
  IWorksheet worksheet = workbook.Worksheets[0];
 
  //Sample data
  worksheet.Range["A1:K20"].Text= "Locked";
 
  //A1:A10 will not be protected
  worksheet.Range["A1:A10"].CellStyle.Locked = false;
 
  worksheet.Range["A1:A10"].Text = "UnLocked";
 
  worksheet.Protect("syncfusion");
  
  //Save the workbook to disk in xlsx format
  workbook.SaveAs("Output.xlsx");
}

VB.NET

'Create an instance of ExcelEngine
Using excelEngine As ExcelEngine = New ExcelEngine
 
  'Set the default application version as Excel 2016
  excelEngine.Excel.DefaultVersion = ExcelVersion.Excel2016
 
  'Create a workbook with a worksheet
  Dim workbook As IWorkbook = excelEngine.Excel.Workbooks.Create(1)
 
  'Access first worksheet from the workbook instance
  Dim worksheet As IWorksheet = workbook.Worksheets(0)
 
  'Sample data
  worksheet.Range["A1:K20"].Text= "Locked"
 
  'A1:A10 will not be protected. 
  worksheet.Range["A1:A10"].CellStyle.Locked = false
 
  worksheet.Range["A1:A10"].Text = "UnLocked"
 
  worksheet.Protect("syncfusion")
 
  'Save the workbook to disk in xlsx format
  workbook.SaveAs("Output.xlsx")
 
End Using

A complete working example of how to add image to Excel header in C#/VB.NET can be downloaded from Protect-Certains-Cells.zip.

By executing the program, you will get the Excel file. You can edit the “Unlocked” text cells but if you are trying to edit the “Locked” text cells, the popup will throw in Excel as below.

Output Excel document

Take a moment to peruse the documentation, where you can find basic worksheet data manipulation options along with features like Conditional Formatting, worksheet calculations through Formulas, adding Charts in worksheet or workbook, organizing and analyzing data through Tables and Pivot Tables, appending multiple records to worksheet using Template Markers, and most importantly PDF and Image conversions with code examples.

Refer here to explore the rich set of Syncfusion Excel (XlsIO) library features.

Conclusion

I hope you enjoyed learning how to protect certain cells in C#, VB.NET and WinForms Excel.

You can refer to our WinForms Excel feature tour page to know about its other groundbreaking feature representations and documentation, and how to quickly get started for configuration specifications. You can also explore our WinForms Excel example to understand how to create and manipulate data.

For current customers, you can check out our components from the License and Downloads page. If you are new to Syncfusion, you can try our 30-day free trial to check out our other controls.

If you have any queries or require clarifications, please let us know in the comments section below. You can also contact us through our support forums, Direct-Trac, or feedback portal. We are always happy to assist you!