写入C＃中另一个进程（Windows服务）正在使用的文件

Question

Is there any way I can write to a file that is being used by another process? I have a windows service that creates logs and locks the file until the service is stopped. I have another program that backs up the contents of a textfile and clears the original. When I tried my C# program to backup and clear the log that my other service is using it generated an error: "The process cannot access the file because it is being used by another process"..

I've been searching and have known that you have to check for a file if it is locked then wait for it until it is not being used by another program. I need a code that enables to write to a locked file. Is that possible?

This is my sample windows service code that logs to files every 3 minutes:

private Timer timer = new Timer();
private static FileStream fs = new FileStream(@"D:\Hello.txt", FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
private StreamWriter sw = new StreamWriter(fs);

protected override void OnStart(string[] args)
{
    timer.Elapsed += new ElapsedEventHandler(WriteText);
    timer.Interval = 50000; //5 minutes
    timer.Start();
}
public void WriteText(object source, ElapsedEventArgs e)
{
    sw.WriteLine(DateTime.Now);
}
protected override void OnStop()
{
    sw.Close();
    sw.Dispose();
    fs.Close();
    fs.Dispose();   
}

It is required for me to not close the stream unless the service is stopped.

Answer 1

Are you tied down to using a StreamWriter? You may want to look into using something like log4net for logging. You can configure it to roll over logs and you could backup from there, or just simply use that as your backups.