下面的代码示例显示了如何使用 IO 类来创建目录列表。
[C#]
using System;
using System.IO;
class DirectoryLister
{
public static void Main(String[] args)
{
DirectoryInfo dir = new DirectoryInfo(".");
foreach (FileInfo f in dir.GetFiles("*.cs"))
{
String name = f.FullName;
long size = f.Length;
DateTime creationTime = f.CreationTime;
Console.WriteLine("{0,-12:N0} {1,-20:g} {2}", size,
creationTime, name);
}
}
}
BinaryWriter 和 BinaryReader 类用于读取和写入数据，而不是字符串。下面的代码示例示范了向新的、空文件流 (Test.data) 写入数据及从该文件读取数据。在当前目录中创建了数据文件之后，也就同时创建了相关的 BinaryWriter 和 BinaryReader，BinaryWriter 用于向 Test.data 写入整数 0 到 10，Test.data 在文件尾留下了一个文件指针。在将文件指针设置回初始位置后，BinaryReader 读出指定的内容。
[C#]
using System;
using System.IO;
class MyStream {
private const string FILE_NAME = "Test.data";
public static void Main(String[] args) {
// Create the new, empty data file.
if (File.Exists(FILE_NAME)) {
Console.WriteLine("{0} already exists!", FILE_NAME);
return;
}
FileStream fs = new FileStream(FILE_NAME, FileMode.CreateNew);
// Create the writer for data.
BinaryWriter w = new BinaryWriter(fs);
// Write data to Test.data.
for (int i = 0; i < 11; i++) {
w.Write( (int) i);
}
w.Close();
fs.Close();
// Create the reader for data.
fs = new FileStream(FILE_NAME, FileMode.Open, FileAccess.Read);
BinaryReader r = new BinaryReader(fs);
// Read data from Test.data.
for (int i = 0; i < 11; i++) {
Console.WriteLine(r.ReadInt32());
w.Close();
}
}
}
StreamWriter 和 StreamReader 向流写入字符并从流读取字符。下面的代码示例打开 log.txt 文件（如果文件不存在则创建文件）以进行输入，并将信息附加到文件尾。然后将文件的内容写入标准输出，以便显示出来。
[C#]
using System;
using System.IO;
class DirAppend
{
public static void Main(String[] args)
{
StreamWriter w = File.AppendText("log.txt");
Log ("Test1", w);
Log ("Test2", w);
// Close the writer and underlying file.
w.Close();
// Open and read the file.
StreamReader r = File.OpenText("log.txt");
DumpLog (r);
}
public static void DumpLog (StreamReader r)
{
// While not at the end of the file, read and write lines.
String line;
while ((line=r.ReadLine())!=null)
{
Console.WriteLine(line);
}
r.Close();
}
}
从文件读取文本
下面的代码示例读取整个文件，并在检测到文件尾时发出通知。
[C#]
using System;
using System.IO;
public class TextFromFile {
private const string FILE_NAME = "MyFile.txt";
public static void Main(String[] args) {
if (!File.Exists(FILE_NAME)) {
Console.WriteLine("{0} does not exist!", FILE_NAME);
return;
}
StreamReader sr = File.OpenText(FILE_NAME);
String input;
while ((input=sr.ReadLine())!=null) {
Console.WriteLine(input);
}
Console.WriteLine ("The end of the stream has been reached.");
sr.Close();
}
}
下面的代码示例创建一个新文本文件并向其写入一个字符串。
[C#]
using System;
using System.IO;
public class TextToFile {
private const string FILE_NAME = "MyFile.txt";
public static void Main(String[] args) {
if (File.Exists(FILE_NAME)) {
Console.WriteLine("{0} already exists!", FILE_NAME);
return;
}
StreamWriter sr = File.CreateText(FILE_NAME);
sr.WriteLine ("This is my file.");
sr.WriteLine ("I can write ints {0} or floats {1}, and so on.",
1, 4.2);
sr.Close();
}
}
代码定义字符串并将其转换为字符数组，然后，可以使用适当的 StringReader.Read 方法按需要读取该字符数组。
[C#]
using System;
using System.IO;
public class CharsFromStr
{
public static void Main(String[] args)
{
// Create a string to read characters from.
String str = "Some number of characters";
// Size the array to hold all the characters of the string,
// so that they are all accessible.
char[] b = new char[24];
// Create a StringReader and attach it to the string.
StringReader sr = new StringReader(str);
// Read 13 characters from the array that holds the string, starting
// from the first array member.
sr.Read(b, 0, 13);
// Display the output.
Console.WriteLine(b);
// Close the StringReader.
sr.Close();
}
}
