数据库，SqlCommand未包含Open的定义

Question

VS2019，写出的程序在查询窗口的Open可用，在写增加的窗口功能时不可用了

但是在search的时候可用

后面附代码

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Data.SqlClient;

namespace WinFormsApp1
{
    public partial class tic_add : Form
    {
        tic_search ss = new tic_search();
        public tic_add()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            string strsql = "insert into tic(tno,cno,rnum,seat,way)";
            strsql += "values(@tno,@cno,@rnum,@seat,@way)";
            SqlParameter sp_tno = new SqlParameter("@tno",tno_add.Text);
            SqlParameter sp_cno = new SqlParameter("@cno", cno_add.Text);
            SqlParameter sp_rnum = new SqlParameter("@rnum", rnum_add.Text);
            SqlParameter sp_seat = new SqlParameter("@seat", seat_add.Text);
            SqlParameter sp_way = new SqlParameter("@way", way_add.Text);
            /*string strsex="女"
             * SqlParameter sp_ssex=new SqlParameter("@ssex",strsex);*/
            using (SqlCommand con = new SqlCommand(ss.strcon))
            {
                con.Open();
                using (SqlCommand cmd = new SqlCommand(strsql, con))
                {
                    cmd.Parameters.Add(sp_tno);
                    cmd.Parameters.Add(sp_cno);
                    cmd.Parameters.Add(sp_rnum);
                    cmd.Parameters.Add(sp_seat);
                    cmd.Parameters.Add(sp_way);
                }

            }
        }
    }
}

代码没有写完

Answer 1

SqlConnection 有Open函数

SqlCommand 没有Open函数

请确认！