ASP.NET入门之向文件操作
Code向文件写入文本using System;
using System.IO;
class Test
{
public static void Main()
{
// Create an instance of StreamWriter to write text to a file.
// The using statement also closes the StreamWriter.
using (StreamWriter sw = new StreamWriter("TestFile.txt"))
{
// Add some text to the file.
sw.Write("This is the ");
sw.WriteLine("header for the file.");
sw.WriteLine("-------------------");
// Arbitrary objects can also be written to the file.
sw.Write("The date is: ");
sw.WriteLine(DateTime.Now);
}
}
}
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();
}
}
从文件读取文本
using System;
using System.IO;
class Test
{
public static void Main()
{
try
{
// Create an instance of StreamReader to read from a file.
// The using statement also closes the StreamReader.
using (StreamReader sr = new StreamReader("TestFile.txt"))
{
String line;
// Read and display lines from the file until the end of
// the file is reached.
while ((line = sr.ReadLine()) != null)
{
Console.WriteLine(line);
}
}
}
catch (Exception e)
{
// Let the user know what went wrong.
Console.WriteLine("The file could not be read:");
Console.WriteLine(e.Message);
}
}
}
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();
}
}
File.AppendText 方法 创建一个 StreamWriter，它将 UTF-8 编码文本追加到现有文件。
public static StreamWriter AppendText(
string path
);
参数
path
要向其中追加内容的文件的路径。
返回值
一个 StreamWriter，它将 UTF-8 编码文本追加到现有文件。
将文本追加到文件
using System;
using System.IO;
class Test
{
public static void Main()
{
string path = @"c: empMyTest.txt";
// This text is added only once to the file.
if (!File.Exists(path))
{
// Create a file to write to.
using (StreamWriter sw = File.CreateText(path))
{
sw.WriteLine("Hello");
sw.WriteLine("And");
sw.WriteLine("Welcome");
}
}
// This text is always added, making the file longer over time
// if it is not deleted.
using (StreamWriter sw = File.AppendText(path))
{
sw.WriteLine("This");
sw.WriteLine("is Extra");
sw.WriteLine("Text");
}
// Open the file to read from.
using (StreamReader sr = File.OpenText(path))
{
string s = "";
while ((s = sr.ReadLine()) != null)
{
Console.WriteLine(s);
}
}
}
}
using System;
using System.IO;
class Test
{
public static void Main()
{
FileInfo fi = new FileInfo(@"c: empMyTest.txt");
// This text is added only once to the file.
if (!fi.Exists)
{
//Create a file to write to.
using (StreamWriter sw = fi.CreateText())
{
sw.WriteLine("Hello");
sw.WriteLine("And");
sw.WriteLine("Welcome");
}
}
// This text will always be added, making the file longer over time
// if it is not deleted.
using (StreamWriter sw = fi.AppendText())
{
sw.WriteLine("This");
sw.WriteLine("is Extra");
sw.WriteLine("Text");
}
//Open the file to read from.
using (StreamReader sr = fi.OpenText())
{
string s = "";
while ((s = sr.ReadLine()) != null)
{
Console.WriteLine(s);
}
}
}
}
=====================================
using System;
using System.IO;
public class AppendTextTest
{
public static void Main()
{
// Create a reference to a file, which might or might not exist.
// If it does not exist, it is not yet created.
FileInfo fi = new FileInfo("temp.txt");
// Create a writer, ready to add entries to the file.
StreamWriter sw = fi.AppendText();
sw.WriteLine("Add as many lines as you like
");sw.WriteLine("Add another line to the output
");sw.Flush();
sw.Close();
// Get the information out of the file and display it.
// Remember that the file might have other lines if it already existed.
StreamReader sr = new StreamReader(fi.OpenRead());
while (sr.Peek() != -1)
Console.WriteLine( sr.ReadLine() );
}
}
移动一个文件将指定文件移到新位置，并提供指定新文件名的选项。public static void Move(string sourceFileName,string destFileName);参数sourceFileName 要移动的文件的名称。 destFileName 文件的新路径。 using System;
using System.IO;
class Test
{
public static void Main()
{
string path = @"c: empMyTest.txt";
string path2 = path + "temp";
try
{
if (!File.Exists(path))
{
// This statement ensures that the file is created,
// but the handle is not kept.
using (FileStream fs = File.Create(path)) {}
}
// Ensure that the target does not exist.
if (File.Exists(path2))
File.Delete(path2);
// Move the file.
File.Move(path, path2);
Console.WriteLine("{0} was moved to {1}.", path, path2);
// See if the original exists now.
if (File.Exists(path))
{
Console.WriteLine("The original file still exists, which is unexpected.");
}
else
{
Console.WriteLine("The original file no longer exists, which is expected.");
}
}
catch (Exception e)
{
Console.WriteLine("The process failed: {0}", e.ToString());
}
}
}
将一个文件移动至另一位置并重命名该文件。using System;
using System.IO;
public class MoveToTest
{
public static void Main()
{
// Create a reference to a file, which might or might not exist.
// If it does not exist, it is not yet created.
FileInfo fi = new FileInfo("temp.txt");
// Create a writer, ready to add entries to the file.
StreamWriter sw = fi.AppendText();
sw.WriteLine("Add as many lines as you like
");sw.WriteLine("Add another line to the output
");sw.Flush();
sw.Close();
// Ensure that the target file does not exist, since this is disallowed.
if (File.Exists("newTemp.txt"))
File.Delete("newTemp.txt");
// Move this file to another file.
fi.MoveTo("newTemp.txt");
// Get the information out of the new file and display it.
StreamReader sr = new StreamReader( fi.OpenRead() );
Console.WriteLine("{0}This is the information in the new file "{1}":", Environment.NewLine, fi.Name);
while (sr.Peek() != -1)
Console.WriteLine( sr.ReadLine() );
}
}
