压缩和解压，文件读取练习

压缩

先读取，再写入。只是在写入的时候，需要根据规则写入，如果用用压缩流写入，就成了压缩。

 using (FileStream fs = new FileStream("yasuo.txt", FileMode.Open, FileAccess.Read))
            {
                byte[] buffer = new byte[1024 * 1024 * 5];
                int readCount = fs.Read(buffer, 0, buffer.Length);
                using (FileStream fWrite = new FileStream("newYaSuo.txt", FileMode.Create, FileAccess.Write))
                {
                    using (GZipStream zip = new GZipStream(fWrite, CompressionMode.Compress))
                    {
                        while (readCount > 0)
                        {
                            zip.Write(buffer, 0, readCount);
                            readCount = fs.Read(buffer, 0, buffer.Length);
                        }
                    }

                }
            }

解压

解压前，先要读取，然后再写入。只是开始读取后，如果直接写入，写入的还是以前压缩的东西，所以在写入前先要解压。 

using (FileStream fs = new FileStream("newYaSuo.txt", FileMode.Open, FileAccess.Read))
            {
                byte[] buffer = new byte[1024 * 1024 * 5];
                using (GZipStream zip = new GZipStream(fs, CompressionMode.Decompress))
                {
                    int readCount = zip.Read(buffer, 0, buffer.Length);
                    using (FileStream fWrite = new FileStream("newJieYaSuo.txt", FileMode.Create, FileAccess.Write))
                    {

                        while (readCount > 0)
                        {
                            fWrite.Write(buffer, 0, readCount);
                            readCount = zip.Read(buffer, 0, buffer.Length);
                        }

                    }
                }
            }

文件读取练习：人员信息维护

public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            BindListBox();

        }

        private void BindListBox()
        {
            List<Person> list = new List<Person>();
            string line = string.Empty;
            
            //读取文件中的数据
            using (StreamReader sRead = new StreamReader("person.txt", Encoding.Default))
            {
                while ((line=sRead.ReadLine())!=null)
                {
                    string[] strs = line.Split(',');
                    Person p = new Person();
                    p.Name = strs[0];
                    p.Age = Convert.ToInt32(strs[1]);
                    list.Add(p);
                }
            }

            lbPersonList.DataSource = list;
            lbPersonList.DisplayMember = "Name";
            lbPersonList.ValueMember = "Age";
        }

        private void btnAdd_Click(object sender, EventArgs e)
        {
            using (StreamWriter sWrite=new StreamWriter("person.txt", true,Encoding.Default))
            {
                sWrite.WriteLine(string.Format("{0},{1}",txtName.Text.Trim(),txtAge.Text.Trim()));
                //lbPersonList.Items.Add(txtName.Text.Trim());
                
            }
            BindListBox();
        }

        private void lbPersonList_SelectedIndexChanged(object sender, EventArgs e)
        {
            Person p = lbPersonList.SelectedItem as Person;
            if (p!=null)
            {
                txtName.Text = p.Name;
                txtAge.Text = p.Age.ToString();
            }
        }

        private void btnClear_Click(object sender, EventArgs e)
        {
            txtAge.Text = "";
            txtName.Text = "";
        }
    }

    public class Person
    {
        public string Name { get; set; }

        public int Age { get; set; }
    }