'Password Protecting an Excel file in C#

Does anyone know the syntax for this? I've been looking everywhere and all I can find is C++ code for this. I'm trying to password protect an excel file programatically using the System.IO.Packaging namespace.

Any ideas?

Additional notes:

I'm NOT using the Excel interop--but instead the System.IO.Packaging namespace to encrypt and password protect the excel file.

c++sharpexcelpasswordspassword-protection


Solution 1:[1]

It's not possible using System.IO.Packaging. You will have to use Microsoft.Office.Interop.Excel using the Worksheet.SaveAs method. This requires Excel being installed on your target system.

Solution 2:[2]

You will have to use the SaveAs method on the Worksheet. It has a parameter to set a password. Here is an example in VB which can be converted to C#

http://www.codeproject.com/KB/office/Excel_Security.aspx

Solution 3:[3]

using System.IO;
using Excel=Microsoft.Office.Interop.Excel;

class ExcelUtil
{
    public  string Filename;

    private  Excel.Application oexcel;

    private Excel.Workbook obook;

    private  Excel.Worksheet osheet;
    public void createPwdExcel()
    {
        try
        {
            // File name and path, here i used abc file to be 
            // stored in Bin directory in the sloution directory
            //Filename = (AppDomain.CurrentDomain.BaseDirectory + "abc.xls");
            if (File.Exists(Filename))
            {
                File.Delete(Filename);
            }

            if (!File.Exists(Filename))
            {
                // create new excel application
                Excel.Application oexcel = new Excel.Application();
                oexcel.Application.DisplayAlerts = false;
                obook = oexcel.Application.Workbooks.Add(Type.Missing);
                oexcel.Visible = true;
                Console.WriteLine("Generating Auto Report");
                osheet = (Excel.Worksheet)obook.Sheets.Add(Type.Missing, Type.Missing, Type.Missing, Type.Missing);
                osheet.Name = "Test Sheet";
                osheet.get_Range("A1:G1").Merge();
                osheet.get_Range("A1").Value = @"Implementing Password Security on Excel Workbook Using Studio.Net";

                osheet.get_Range("A1").Interior.ColorIndex = 5;
                osheet.get_Range("A1").Font.Bold = true;
                string password = "abc";
                obook.WritePassword = password;
                obook.SaveAs("Chandra.xlsx");
                // otherwise use the folowing one
                // TODO: Labeled Arguments not supported. Argument: 2 := 'password'
                // end application object and session
                osheet = null;
                obook.Close();
                obook = null;
                oexcel.Quit();
                oexcel = null;
            }

        }
        catch (Exception ex)
        {

        }

    }
}

Solution 4:[4]

Download Microsoft.Office.Interop.Excel from NuGet Package. Password protect Excel file using c# code below

using Excel = Microsoft.Office.Interop.Excel; 

Excel.Application xlApp = new Excel.Application();
        Excel.Workbook xlWorkbook = xlApp.Workbooks.Open(srcFile);
        
            //protect the whole workbook  
            xlWorkbook.Password = "passwordString";
            xlWorkbook.SaveAs(dstFile);
            xlWorkbook.Close();
            xlApp.Quit();

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 Dirk Vollmar
Solution 2 user110190
Solution 3 johnnyRose
Solution 4 rajquest

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