不安全代码只会在使用/unsafe编译的情况下出现？？？
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

using System.Runtime.InteropServices;
namespace WindowsSecretPipe
{
  public partial class ICReader : Form
  {
  public ICReader()
  {
  InitializeComponent();
  }

  private void button1_Click(object sender, EventArgs e)
  {
  //初始化
  int icdev = IC.auto_init(0, 9600);
  if (icdev < 0)
  MessageBox.Show("端口初始化失败,请检查接口线是否连接正确。", "错误提示", MessageBoxButtons.OK, MessageBoxIcon.Information);
  int md = IC.setsc_md(icdev, 1); //设备密码格式
  int i = IC.dv_beep(icdev, 10); //发出蜂鸣声
  unsafe
  {
  Int16 status = 0;
  Int16 result = 0;
  result = IC.get_status(icdev, &status);
  if (result != 0)
  {
  MessageBox.Show("设备当前状态错误！");
  int d1 = IC.ic_exit(icdev); //关闭设备
  return;
  }

  if (status != 1)
  {
  MessageBox.Show("请插入ＩＣ卡");
  int d2 = IC.ic_exit(icdev); //关闭设备
  return;
  }
  }
  unsafe
  {
  char str = 'a';
  int read = -1;
  for (int j = 0; j < 6; j++)
  {
  read = IC.srd_4442(icdev, 33 + j, 1, &str);
  textBox1.Text = textBox1.Text + Convert.ToString(str);
  }
  if (read == 0)
  MessageBox.Show("ＩＣ卡中数据读取成功！");
  }
  int d = IC.ic_exit(icdev); //关闭设备
  }
  }
}
[StructLayout(LayoutKind.Sequential)]
public unsafe class IC
{

  //对设备进行初始化
  [DllImport("Mwic_32.dll", EntryPoint = "auto_init", SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
  public static extern int auto_init(int port, int baud);
  //设备密码格式
  [DllImport("Mwic_32.dll", EntryPoint = "setsc_md", SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
  public static extern int setsc_md(int icdev, int mode);
  //获取设备当前状态
  [DllImport("Mwic_32.dll", EntryPoint = "get_status", SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
  public static unsafe extern Int16 get_status(int icdev, Int16* state);
  //关闭设备通讯接口
  [DllImport("Mwic_32.dll", EntryPoint = "ic_exit", SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConvention.StdCall)]
  public static extern int ic_exit(int icdev);
  //使设备发出蜂鸣声
  [DllImport("Mwic_32.dll", EntryPoint = "dv_beep", SetLastError = true, CharSet = CharSet.Ansi, ExactSpelling = true, CallingConvention = CallingConventio