Backup/Restore SQL Server 2016 LocalDB

Question

I have SQL Server 2016 LocalDB (.mdf file) and I want make backup of my database. I use the code shown below, but it does not work. I tested all code that exists in stackoverflow, but none of them worked.

Here is my code (this code works perfectly on SQL Server 2014 but does not work on localdb):

SqlConnection connect;
string con = @"Data Source=(LocalDB)\MSSQLLocalDB;AttachDbFilename=|DataDirectory|\Database\ClassSRM.mdf;Integrated Security=True";
connect = new SqlConnection(con);
connect.Open();

SqlCommand command = new SqlCommand(@"backup database " + Application.StartupPath + @"\Database\ClassSRM.mdf" + " to disk ='" + strFileName + "'", connect);

command.ExecuteNonQuery();
connect.Close();