C# WebSocket Fleck 调用非托管C++ DLL 实现通信（使用stringbuilder接收）

 [DllImport(@"XXX.dll", CallingConvention = CallingConvention.StdCall)]
public static extern int XXX(string strin,StringBuilder strout);
        static void Main()
        {
            FleckLog.Level = LogLevel.Debug;
            var allSockets = new List<IWebSocketConnection>();
            var server = new WebSocketServer("ws://0.0.0.0:8181");
            server.Start(socket =>
            {
                socket.OnOpen = () =>
                {
                    Console.WriteLine("Open!");
                    allSockets.Add(socket);
                };
                socket.OnClose = () =>
                {
                    Console.WriteLine("Close!");
                    allSockets.Remove(socket);
                };
                socket.OnMessage = message =>
                {
                    Console.WriteLine(message);
                    message = getDate(message);
                    socket.Send(message);
                };
            });

            var input = Console.ReadLine();
            while (input != "exit")
            {
                input = Console.ReadLine();
            }
        }

private static string getData(string message)
        {
            StringBuilder response = new StringBuilder();
            response.Capacity = 100;//设置字符串最大长度

            var aa = XXX(message, response);
            var result = response.ToString();

            if (result.Substring(0, 2) != "00")
            {
                result = "获取失败";
            }
            return result;
        }

注意：1、DLL传出字符串，C#中使用StringBuilder对象创建变长数组，并设置StringBuilder的Capacity为数组最大长度。将此对象名传递给DLL，使用char*接收

2、Fleck 地址：https://github.com/statianzo/Fleck/