Winform最基础的DBHelper类

PS：我已经忘记了n遍了

 class DBHelper
    {
        //连接数据库
        public static string connstring = @"Data Source=DESKTOP-8HPQ7CU;Initial Catalog=ChaoShiGuanLi;Integrated Security=True";
        public static SqlConnection conn = null;
        //初始化数据库
        public static void lnitconnection()
        {
            if (conn==null)
            {
                //对象不存在创建连接
                conn = new SqlConnection(connstring);
            }
            if (conn.State==ConnectionState.Closed)
            {
                //对象关闭打开连接
                conn.Open();
            }
            if (conn.State==ConnectionState.Broken)
            {
                //对象中断重新连接
                conn.Close();
                conn.Open();
            }

        }
        //查询获取datareader
        public static SqlDataReader GetdataReader(string sqlstr)
        {
            lnitconnection();
            SqlCommand cmd = new SqlCommand(sqlstr, conn);
            return cmd.ExecuteReader(CommandBehavior.CloseConnection);
        }
        //增删改操作
        public static bool ExecuteNonQuery(string sqlstr)
        {
            lnitconnection();
            SqlCommand cmd = new SqlCommand(sqlstr, conn);
            int result = cmd.ExecuteNonQuery();
            conn.Close();
            return result > 0;
        }
        //执行聚合函数
        public static object ExecuteScalar(string sqlstr)
        {
            lnitconnection();
            SqlCommand cmd = new SqlCommand(sqlstr, conn);
            object result = cmd.ExecuteScalar();
            conn.Close();
            return result;
        }
        public static DataTable GetDataTable(string sqlStr)
        {
            lnitconnection();
            DataTable table = new DataTable();
            SqlDataAdapter dap = new SqlDataAdapter(sqlStr, conn);
            dap.Fill(table);
            conn.Close();
            return table;
        }

    }