本帖最后由 wulangxiong 于 2013-1-29 17:58 编辑
System.IO 还为我们提供了BinaryReader 和BinaryWriter 类用于按二进制模式读
写文件它们提供的一些读写方法是对称的比如针对不同的数据结构BinaryReader
提供了ReadByte ReadBoolean ReadInt ReadInt16 ReadDouble ReadString 等方法
而BinaryWriterz 则提供了WriteByte WriteBoolean WriteInt WriteInt16 WriteDouble
WriteString 方法
下面我们举一个通讯录的例子来说明BinaryReader 和BinaryWriter 类是如何使用
的。
using System;
using System.IO;
struct Record{
public
string name;
public
UInt16 age;
public
string phone;
public
string address;
};
//通讯录的记录格式
class
PhoneBook
{
FileStream
f_srm;
string
s_filename;
Record
m_record;
public
PhoneBook(string filename)
{
s_filename
= filename;
}
public
int
Open()
{
//显示初始化界面
Console.WriteLine("1: List Record");
Console.WriteLine("2: Add New Record");
Console.WriteLine("3: Erase Record");
Console.WriteLine("0: Exit");
int
i = Console.Read() -
'0';
return
i;
}
public
void
AddNew()
{
//向通讯录中添加记录
    try{
    f_srm =
new
FileStream(s_filename,FileMode.OpenOrCreate);
    }
    catch
    {
    Console.WriteLine("PhoneBookError!");
    return;
    }
    BinaryWriter pw =
new
BinaryWriter(f_srm);
    pw.Seek(0,SeekOrigin.End);
    string s_temp;
    Console.Write("Name:");
    Console.ReadLine();
    m_record.name = Console.ReadLine();
    pw.WriteString(m_record.name);
    reenter:
    Console.Write("Age: ");
    s_temp = Console.ReadLine();
    try{
    m_record.age = s_temp.ToUInt16();
    }
    catch
    {
    Console.WriteLine("The formatof age is error,please ReEnter");
    goto
reenter;
    }
    pw.Write(m_record.age);
    Console.Write("PhoneNumber: ");
    m_record.phone = Console.ReadLine();
    pw.WriteString(m_record.phone);
    Console.Write("Address:");
    m_record.address = Console.ReadLine();
    pw.WriteString(m_record.address);
    f_srm.Close();
    }
    public
void
List()
    {
//浏览所有记录
    try{
       f_srm =
new
FileStream(s_filename,FileMode.Open);
    }
    catch
    {
    Console.WriteLine("PhoneBookError!");
    return;
    }
    BinaryReader pr =
new
BinaryReader(f_srm);
    Console.WriteLine("Name AgePhone Number Address");
    Console.WriteLine("***************************************");
    while(true)
    {
    try{
    m_record.name = pr.ReadString();
    m_record.age = pr.ReadUInt16();
    m_record.phone = pr.ReadString();
    m_record.address = pr.ReadString();
    }
    catch{return;}
    Console.WriteLine("{0,-9}{1,-6}{2,-18}{3}",m_record.name,
           m_record.age,m_record.phone,m_record.address);
           }
           f_srm.Close();
           }
public
void
Erase()
           {
//清空所有记录
try{
           f_srm =
new
FileStream(s_filename,FileMode.Create);
           }
catch
           {
           Console.WriteLine("PhoneBook Error!");
return;
           }
           f_srm.Close();
           Console.WriteLine("Now the book is empty!");
           }
           }
class
Test
{
public
static
void
Main()
{
PhoneBook pbook =
new
PhoneBook("c:\\c#\\file\\Phone.book");
int
i = pbook.Open();
switch(i)
{
case
1:
pbook.List();
break;
case
2:
pbook.AddNew();
break;
case
3:
pbook.Erase();
}
}
}
}
其中有这么一条语句
Console.WriteLine("{0,-9}{1,-6}{2,-18}{3}",m_record.name,
m_record.age,m_record.phone,m_record.address);
它表示对输出进行格式化{} 中使用的第二个数表示输出占据的屏幕位数正
数表示从右边起计而负数表示从左边起计。