c# - Preventing a user from deleting, modifying, ext -

i need make program reads data text file , changes program state according specific data found in text file, program needs privileges read, write , create text file.

i want users or other software prevented deleting, modifying, or copying file. how begin implement this?

you can achieve in 3 ways:

1) application starts filehandle , lock file. of course work if applications runs (for example service) time

2) adjust priviledges in files security tab , set read only. create technical user write access (works best in domains). open file in program technical user while using impersionation (windowsimpersonationcontext). using simple:

using (new impersonation(domain, username, password)) {     // whatever want } 

a sample class windowsimpersonationcontext (should work charm):

[permissionset(securityaction.demand, name = "fulltrust")] public class impersonation : idisposable {     private readonly safetokenhandle _handle;     private readonly windowsimpersonationcontext _context;      const int logon32_logon_new_credentials = 9;      public impersonation(string domain, string username, string password)     {         var ok = logonuser(username, domain, password,                        logon32_logon_new_credentials, 0, out this._handle);         if (!ok)         {             var errorcode = marshal.getlastwin32error();             throw new applicationexception(string.format("could not impersonate elevated user.  logonuser returned error code {0}.", errorcode));         }          this._context = windowsidentity.impersonate(this._handle.dangerousgethandle());     }      public void dispose()     {         this._context.dispose();         this._handle.dispose();     }      [dllimport("advapi32.dll", setlasterror = true, charset = charset.unicode)]     private static extern bool logonuser(string lpszusername, string lpszdomain, string lpszpassword, int dwlogontype, int dwlogonprovider, out safetokenhandle phtoken);      public sealed class safetokenhandle : safehandlezeroorminusoneisinvalid     {         private safetokenhandle()             : base(true) { }          [dllimport("kernel32.dll")]         [reliabilitycontract(consistency.willnotcorruptstate, cer.success)]         [suppressunmanagedcodesecurity]         [return: marshalas(unmanagedtype.bool)]         private static extern bool closehandle(intptr handle);          protected override bool releasehandle()         {             return closehandle(handle);         }     } } 

another attempt (including using) shown here: open shared file under user , domain?

3) running program different user has access rights - other users have readonly rights (use technical user when registered service or runas /user command)