File creation and naming increment

[PIEBALDconsult]

Store the last number used in a database or the config file or something, that will allow you to manage it.

[Tom Deketelaere]

You could use recursion. steps: Check if file text.txt exist --> if so ad a number to the name and redo check (exacute untill check is false (increase the number everytime) --> if not create/save the file with the current name If you want I have some vb.net code that does this somewhere but can't look it up at the moment since I'm not at the office.

[Lost User]

1. Get all filenames in a directory 2) Sort the list of names using a custom comparer to put your files ("TextNN.txt") with the highest number first 3) Take the first file after the sort and extract the number regards

[Luc Pattyn]

Hi, if the number embedded in the filename uses a fixed format with leading zeroes the alphabetical order is the numeric order too, so no special comparer would be needed. :)

Luc Pattyn [Forum Guidelines] [My Articles]

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Good riddance W

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modified on Friday, June 10, 2011 12:08 PM

[Ennis Ray Lynch Jr]

You are creating a web form to monitor a file on a network share? Everyone else has addressed your questions adequately so I will just pose two alternatives which may be easier, if sequence is not important but uniqueness is use a GUID, if both are important a time stamp is also a good option.

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[Terick]

Thank you all for your posts. It's been helpful. I'm still a little stuck, but I have the general idea. The files may get deleted, so I will need to take that into account. Also, I'm not using any database and for this application wont be using one. This is what I have so far. Please let me know if there are better methods:

public void filecount(string file)
{
int x;
int y;
string file;

int filepaths = Directory.GetFiles(@"C:\Desktop\Request", "*txt").Length;
x = filepaths +1;

StreamWriter sw;
sw = File.CreateText(@"C:\Desktop\Request\Text" +y +".txt");
file = Path.GetFileName(@"C:\Desktop\Request\Text" +y +".txt").ToString;
sw.Close();

return file;
}

public void btn_Click(object sender, EventArgs e)
{
filecount(file);
}

Thanks again for helping a newbie out!

[Terick]

The webform is used for more than just monitoring the text file. I need to have a text file as it is being used by another program. I originally thought of adding a timestamp into the filename to differentiate however, I thought an incrementing integer would be easier.

[Ennis Ray Lynch Jr]

Incrementing the integer requires the following steps: 1) Find the highest file 2) Attempt to create the next number 3) Repeat on failure A time stamp requires: 1) Attempt to create the file 2) Repeat on failure Unfortunately, only the Win32 API allows you to do this without a try catch loop which I find poor practice.

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If you don't ask questions the answers won't stand in your way.
Most of this sig is for Google, not ego.

[Lost User]

Luc Pattyn wrote:

if the number embedded in the filename uses a fixed format with leading zeroes the alphabetical order is the numeric order too, so no special comparer would be needed.

True, but this requires two things: 1) the number has leading zeros 2) the "TextNN" files are the only files in this folder, no other files like "AAA" and "ZZZ" which would put the "TextNN" files to the middle of the list. Duh, forgot you can use a filter pattern to get the filenames :) With a custom comparer you're on the safe side :)

[Lost User]

That's how I'd do it:

string[] logfiles = Directory.GetFiles(@"../Files/", @"Text*.txt");
Array.Sort(logfiles, CompareFileNumbers);

int highestNumber = int.Parse(Regex.Match(logfiles[0], @"(\d+)").Value);

with the custom comparer being:

public static int CompareFileNumbers(string fileA, string fileB)
{
Regex regexNumber = new Regex(@"(\d+)");

int fileNumberA = int.Parse(regexNumber.Match(fileA).Value);
int fileNumberB = int.Parse(regexNumber.Match(fileB).Value);

return -fileNumberA.CompareTo(fileNumberB); // the miuns sign will sort descending

}

Tested and it works. You need to add error checking though in case the filenames don't have numbers (the regexes will fail) and other cases. regards

[PIEBALDconsult]

You can check to see if a file with that name already exists.

[Ennis Ray Lynch Jr]

Doesn't work in concurrent systems as the check for existence and creation have to be the same act, otherwise File.Exists then File.Create can fail.

Need software developed? Offering C# development all over the United States, ERL GLOBAL, Inc is the only call you will have to make.
If you don't ask questions the answers won't stand in your way.
Most of this sig is for Google, not ego.

[PIEBALDconsult]

I know. I don't think there's any way around a try/catch. I would still opt for a database.

[Ennis Ray Lynch Jr]

http://msdn.microsoft.com/en-us/library/aa363858(VS.85).aspx[^]

Need software developed? Offering C# development all over the United States, ERL GLOBAL, Inc is the only call you will have to make.
If you don't ask questions the answers won't stand in your way.
Most of this sig is for Google, not ego.

[PIEBALDconsult]

Didn't the original poster mention the API?

[Ennis Ray Lynch Jr]

??

Need software developed? Offering C# development all over the United States, ERL GLOBAL, Inc is the only call you will have to make.
If you don't ask questions the answers won't stand in your way.
Most of this sig is for Google, not ego.

[Terick]

I'm using C# with ASP.NET.

[Ennis Ray Lynch Jr]

Using the Win32 API is a perfectly valid way to overcome limitations in .NET. (Or at least a way to cut off your nose to spite your face)

Need software developed? Offering C# development all over the United States, ERL GLOBAL, Inc is the only call you will have to make.
If you don't ask questions the answers won't stand in your way.
Most of this sig is for Google, not ego.

[PIEBALDconsult]

Oh, no, I see, you did.

[riced]

This won't work - in fact I don't think it will compile. 1 The return type is void but the function tries to return a string. 2 The parameter name (file) conflicts with the local variable also called file. 3 The value of y is not set but is used to construct the file name. Couple of other comments. 1 Why use the x and y variables when you have filepaths. You could just set it to Directory.GetFiles(@"C:\Desktop\Request", "*txt").Length + 1. Then use it instead of x or y. 2 This approach does not deal with deleted files. Suppose there are three files originally (text1.txt, text2.txt, text3.txt). Then text1.txt is deleted. What will the file count be? 3 The function is named filecount but it actually tries to return the next filename. 4 Read some of the suggestions carefully - there's good stuff in them that should solve the problem. Regards David R