Question

我有一些代码从FileSystemWatcher类输出数据，虽然每次输出一行到test.txt，它会覆盖前一个条目，有没有办法阻止这种情况发生？

有问题的代码：

static void FileWatcher_Created(object sender, FileSystemEventArgs e)
{

    using (StreamWriter fileWriter = new StreamWriter("test3.txt"))
    {
        var data = true;
        fileWriter.Write("C:\\" + e.Name + Environment.NewLine);
    }

完整代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.IO;

namespace FileWatcherr
{
class Program
{    
    static void Main(string[] args)
    {
        string dirPath = "C:\\";
        FileSystemWatcher fileWatcher = new FileSystemWatcher(dirPath); 
        fileWatcher.IncludeSubdirectories = true;  
        fileWatcher.Filter = "*.exe";    
        // fileWatcher.Filter = "C:\\$Recycle.Bin";   
        //  fileWatcher.Changed += new FileSystemEventHandler(FileWatcher_Changed);   
        fileWatcher.Created += new FileSystemEventHandler(FileWatcher_Created);    
        //  fileWatcher.Deleted += new FileSystemEventHandler(FileWatcher_Deleted);  
        //  fileWatcher.Renamed += new RenamedEventHandler(FileWatcher_Renamed);    
        fileWatcher.EnableRaisingEvents = true;      

        // updated code


        Console.ReadKey(); 
    }



        static void FileWatcher_Renamed(object sender, RenamedEventArgs e)
        {
            Console.WriteLine(e.OldName + " was renamed to " + e.Name);
        }

        static void FileWatcher_Deleted(object sender, FileSystemEventArgs e)

        {
            Console.WriteLine(e.Name + " was deleted");
        }

        static void FileWatcher_Created(object sender, FileSystemEventArgs e)
        {

            using (StreamWriter fileWriter = new StreamWriter("test3.txt"))
            {
                var data = true;
                fileWriter.Write("C:\\" + e.Name + Environment.NewLine);
            }

        }

        static void FileWatcher_Changed(object sender, FileSystemEventArgs e)
        {
            Console.WriteLine(e.Name + "");
        }
    }
}

Answer 1

编辑您的代码如下。 StreamWriter的第二个参数是我们是否应该追加或覆盖。设置为true表示追加，false表示覆盖（默认为问题）

   using (StreamWriter fileWriter = new StreamWriter("test3.txt", true))
    {
        var data = true;
        fileWriter.WriteLine(Path.Combine("C:\\", e.Name));
    }

有关此构造函数的更多信息，请访问http://msdn.microsoft.com/en-us/library/36b035cb.aspx

Answer 2

考虑打开要附加的文件：

    using (StreamWriter fileWriter = new StreamWriter("test3.txt", true))
    {
        var data = true;
        fileWriter.WriteLine("C:\\" + e.Name);
    }

请注意，最好使用WriteLine方法。

Answer 3

尝试

using (StreamWriter fileWriter = new StreamWriter("test3.txt", true))
{
...
}

Answer 4

替换

new StreamWriter("test3.txt")

通过

new StreamWriter("test3.txt", true)

这将使流附加到文件。

Answer 5

StreamWriter类有一个重载构造函数，它接受第二个bool参数，该参数指定是否要追加到现有文件。 More information here.

C＃将文本输出到新行的文件

5 个答案: