Login Function of C#

public bool _Login(string Username, string Password, string connection, string TableName)
{
   string _username = Username;
   string _password = Password;
   string _Query = "SELECT * FROM'"+TableName+"' WHERE Username='"+_username+"'AND Password='"+_password+"'";
   string _Connection = connection;
   SqlConnection Con = new SqlConnection(_Connection);
   Con.Open();
   SqlCommand cmd = new SqlCommand(_Query,Con);
   SqlDataReader Dr = cmd.ExecuteReader();
   while (Dr.Read())
   {
      if (_username == Dr["Username"].ToString() && _password == Dr["Password"].ToString())
         {
               return true;
         }
   }
   return false;
}