How to: Protect a Worksheet

You can protect a worksheet to lock the cells so that end-users can only perform a specific (restricted) set of actions specified by the WorksheetProtectionPermissions enumeration member. To accomplish this, use the Worksheet.Protect method as illustrated in the following code snippet:

Worksheet worksheet = workbook.Worksheets[0];

// Protect a worksheet. Prevent users from making changes to worksheet elements.
if (!worksheet.IsProtected)
    worksheet.Protect("password", WorksheetProtectionPermissions.Default);
workbook.BeginUpdate();
worksheet["C3:F8"].Borders.SetOutsideBorders(Color.Red, BorderLineStyle.Thin);
worksheet["D5:E6"].Merge();
worksheet["D5"].Value = "Try to change me!";
worksheet["D5"].Alignment.Vertical = SpreadsheetVerticalAlignment.Center;
workbook.EndUpdate();

To remove protection, the end-user can invoke the Protect Sheet dialog. In code, use the Worksheet.Unprotect method.