我的代码如下:
     public partial class Form1 : Form
    {
        [DllImport("LOTcontroller.dll")]
        private static extern HANDLE OpenPort(int port,int baud);
        [DllImport("LOTcontroller.dll")]
        private static extern BOOL ClosePort(HANDLE m_hComm);
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            HANDLE a = OpenPort(2,9600);
            bool b = CloseReason(a);
            if (b == true)
            {
                MessageBox.Show("已经关闭!");
            }
        }
    }

在运行的时候提示:缺少Using 指令或程序集

在线等