How to use Filter and sort of my protected Excel sheet in win c#

[Ganeshtpt]

I am using microsoft.Interop for all my excel related application.

In one of my application, i just want to use Sort and Auto Filter of my protected Excel Sheet.

i think, sort and filter not possible in MS Interop through win c#.

So, i decided to use open source NPOI. below is my code and tell me how to use sort and filter of my protected excel sheet throug NPOI.
below is my win c# code

xlApp = new Excel.Application();
xlWb = xlApp.Workbooks.Open(path);
xlSht = (Excel.Worksheet)workbook.Sheets[ShtName];

//Not Working
xlWb.Worksheets[ShtName].Protection.IsProtected = true;
xlWb.Worksheets[ShtName].Protection.AllowSorting = true;
xlWb.Worksheets[ShtName].Protection.AllowFiltering = true;
//Not working

xlWb.Worksheets[ShtName].Protect(XLwbpwd);

xlWb.Save();
xlWb.Close();
xlApp.Quit();