using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;

using System.IO;

using System.Runtime.InteropServices;

namespace RWFile

{

    public partial class Form1 : Form

    {

        public Form1()

        {

            InitializeComponent();

        }

        //从文件中读结构体

        private void button1_Click(object sender, EventArgs e)

        {

            string strFile = Application.StartupPath + """test.dat";

            if (!File.Exists(strFile))

            {

                MessageBox.Show("文件不存在");

                return;

            }

            FileStream fs = new FileStream(strFile, FileMode.Open, FileAccess.ReadWrite);

            TestStruct ts = new TestStruct();

            byte[] bytData = new byte[Marshal.SizeOf(ts)];

            fs.Read(bytData, 0, bytData.Length);

            fs.Close();

            ts = rawDeserialize(bytData);

            textBox1.Text = ts.dTest.ToString();

            textBox2.Text = ts.uTest.ToString();

            textBox3.Text = Encoding.Default.GetString(ts.bTest); 

        }

        //向文件中写结构体

        private void button2_Click(object sender, EventArgs e)

        {

            string strFile = Application.StartupPath + """test.dat";

            FileStream fs = new FileStream(strFile, FileMode.Create , FileAccess.Write);

            TestStruct ts = new TestStruct();

            ts.dTest = double.Parse(textBox1.Text);

            ts.uTest = UInt16.Parse(textBox2.Text);

            ts.bTest = Encoding.Default.GetBytes(textBox3.Text); 

            byte[] bytData = rawSerialize(ts);

            fs.Write(bytData, 0, bytData.Length);

            fs.Close();

        }

        [StructLayout(LayoutKind.Sequential,CharSet = CharSet.Ansi)] //,Size=16

        public struct TestStruct

        {

            [MarshalAs(UnmanagedType.R8)] //,FieldOffset(0)] 

            public double dTest;

            [MarshalAs(UnmanagedType.U2)] //, FieldOffset(8)]

            public UInt16 uTest;

            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 6)] //, FieldOffset(10)]

            public byte[] bTest;

        }

        //序列化

        public static byte[] rawSerialize(object obj)

        {

            int rawsize = Marshal.SizeOf(obj);

            IntPtr buffer = Marshal.AllocHGlobal(rawsize);

            Marshal.StructureToPtr(obj, buffer, false);

            byte[] rawdatas = new byte[rawsize];

            Marshal.Copy(buffer, rawdatas, 0, rawsize