[DllImport("test.dll")] public static extern void sent(IntPtr msg, int msgLen); [STAThread] public static void Main(string[] args) { var len = 1000; var ar = new byte[len]; // ar 中设置需要发送的内容 var p = Marshal.AllocHGlobal(Marshal.SizeOf(ar)); Marshal.Copy(ar, 0, p, ar.Length); sent(p, len); Marshal.FreeHGlobal(p); }