Problem with writing multiple text files

[as001]

Hi,

I'm writing a windows application in C# using VS 2003.
I got stuck where it has to write multiple output text files. Here's my piece of code:

for loop
{
    Random r = new Random();
    //use millisecond and random to avoid similar filename
    string a_filename = "alert_" + r.Next(1000) + DateTime.Now.Millisecond.ToString() + ".txt";
 
    using (StreamWriter sw = new StreamWriter(a_filename))
    {
        using (TextWriter ssw = TextWriter.Synchronized(sw))
        {
            ssw.Write("some text");
        }
    }
}
 

What happen is let's say it's supposed to write 7 output txt files, but then I found out it's only writing 4.
If I try to using debug mode and step into the code line by line using F11, then it can successfully write 7 output files!
But if I run the application again (not using debug), then it only writes 4 output files.

Does anybody have a suggestion to this problem?

Thanks & Regards,

Adrian

[tlhintoq]

Stop testing with random number and eliminate the possiblity of duplicates.
Make new file names down to 3 points of the second.

String filename = DateTime.Now.To String("HHmmss. fff");

and check if the file already exists before you try to write to it. If it does choose a new name.

[as001]

Argh.. stupid me didn't think of that... I thought it's a slim chance for a random generator to repeat same number. The file is overwriting each other.
Thanks tlhintoq!