C#调用C++编写的DLL

using System.Runtime.InteropServices; //包含DllImport的using指令

namespace TB { public partial class FormTB : Form {

　　　　//声明外部DLL的函数，这里的DLL函数接口已经从文档得知

        [DllImport("USER_COM.dll", EntryPoint = "OpenCOM", CallingConvention = CallingConvention.Cdecl)]
        public static extern bool OpenCOM();

        [DllImport("USER_COM.dll", EntryPoint = "Close_COM", CallingConvention = CallingConvention.Cdecl)]
        public static extern void Close_COM();

        [DllImport("USER_COM.dll", EntryPoint = "COM_RX", CallingConvention = CallingConvention.Cdecl)]
        public static extern int COM_RX(byte[] RX_buff);

        [DllImport("USER_COM.dll", EntryPoint = "COM_Send", CallingConvention = CallingConvention.Cdecl)]
        public static extern int COM_Send(byte cmd, byte data1, byte data2);

        public FormTB()
        {
            InitializeComponent();
            
        }
        //这里以调用DLL里的OpenCOM（）为例
        public Thread rec;
        private void FormTB562_Load(object sender, EventArgs e)
        {
            
            bool op= OpenCOM(); //调用DLL的函数
            Console.WriteLine(" op = " + op);
        }
  }
}

using System.Runtime.InteropServices;