Uppercase and Lowercase in asp.net mvc

TblReg = (from s in _context.TblReg where s.Name.ToLower().ToString().Contains(searchtext) select s).Skip((PageNo - 1) * pagesize).Take(pagesize);

 

combination of Uppercase and Lowercase , how to use a word for Uppercase and Lowercase both "ToLower" the above statement only working for lowercase word