using(SqlConnection conn=new SqlConnection(strconnection))   //创建数据库连接，使用using，会自动释放            {                conn.Open();                 //打开连接                string sql = "insert into newstudent values (@name,@sex,@address,@phone)";  //定义sql语句，@开头为参数                SqlCommand cmd = new SqlCommand(sql, conn);  //实例化sqlcommand，以备传输sql语句到对应的数据库连接中                SqlParameter[] ps ={   //定义数据，为参数赋值                                    new SqlParameter("@name",txtName.Text.Trim()),                                    new SqlParameter("@sex",txtSex.Text.Trim()),                                    new SqlParameter("@address",txtAddress.Text.Trim()),                                    new SqlParameter("@phone",txtPhone.Text.Trim())                                  };                cmd.Parameters.AddRange(ps);                 cmd.ExecuteNonQuery();//执行sql语句                MessageBox.Show("保存成功");            }