C#.NET向现有文件添加文本+创建一个新文本文件并写入一个字符串

向现有文件添加文本:

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);
}
}
}

创建一个新文本文件并写入一个字符串:

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)) // 确认文件是否存在.
{
Console.WriteLine("{0} already exists.", FILE_NAME);
return;
}
using (StreamWriter sw = File.CreateText(FILE_NAME))
{
sw.WriteLine ("This is my file.");
sw.WriteLine ("I can write ints {0} or floats {1}, and so on.",
1, 4.2);
sw.Close();
}
}
}