File Numbering Issue, files number not being updated...

Glenn Patton

Hi All,
I have an interesting problem, I need to create save files in the following format SV_XXXX.msg in a specified location. This I am doing I have a folder with SV_0000.msg to SV_0132.msg
however it will not create SV_0133.msg onwards, it just appears to over write SV_0132.msg with the last data. Is there a reason for this or do I have to rework the way I am calculating the number?
Glenn

25 Replies

Know the answer? Post it — somebody with the same question will find it here.

Vulpes14y ago
Accepted answer
Directory.GetFiles should return an empty array rather than null, if there are no matching files. So this should work and dovetail with your other code:

string[] file_Next = Directory.GetFiles(mydocpath, "SV_????.msg");
int FileCounter = 0; // this value will apply if no files have been created yet

if (file_Next.Length > 0)
{
FileCounter = file_Next.Max(file =>
{
file = Path.GetFileName(file);
return int.Parse(file.Substring(3, 4));
});
FileCounter++;
}
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Glenn Patton14y ago
Hurrrzar!!! it works! Thank you Glenn
0
Glenn Patton14y ago
Right, now a different problem if the folder is empty of SV_XXXX.msg files but will work if SV_0000.msg is in there, could the LINQ stuff be done after a check to see if files exist with

if(string[] file_Next = Directory.GetFiles(@mydocpath, "*.msg") == Null)
{
file_Next = SV_0000.msg;
/* or null to avoid there never being a 0000 */
}

followed by

string[] file_Next = Directory.GetFiles(@mydocpath, "SV_????.msg");

However this problem aside it appears to have cured the issue (at the moment)

Glenn

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Glenn Patton14y ago
Done that, now for testing!
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Vulpes14y ago
Although that's OK for subsequent files, the initial value may need incrementing as well.

I'd try placing this line immediately after the LINQ code:

FileCounter++;
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Glenn Patton14y ago
Well I am increasing FileCounter with a ++ as I am doing this after sw.WriteLine() as below:

sw.WriteLine(Unit_Reply_Modded);

FileCounter++;

strFileCount = Convert.ToString(FileCounter); ;

sw.Close();

As this is in a click routine might it not being seen/skipping it?
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Vulpes14y ago
No, that won't affect the GetFiles method.

If this is happening with the next file to be saved after retrieving the maximum existing file, have you remembered to increase FileCounter by one?
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Glenn Patton14y ago
Oh this is stupid, the same thing has happened again it has stalled at SV_0116.msg it will not create a higher number than 116 this time. Can this be caused by the window the files are being saved in being open?

-=-=-=-=-=-=-=-=-=-=-=-=-
This seems to have righted it self
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Vulpes14y ago
LINQ operates on sequences of values or objects.

A string array is a sequence of strings and most of the LINQ extension methods (such as Max) look at each element of the sequence in turn and perform some operation on it which may generate another sequence.

Here we're passing Max a lambda expression (a method which is written 'inline' and so doesn't need a name).

This lambda expression takes a parameter, file, which represents the next file in the sequence. The compiler knows it's a string as file_Next is a sequence of strings so we don't need to declare a type for it.

In the body of the lambda expression, we first isolate the file name from the full path. We then extract the numeric part from this string, convert it to an integer and return this to Max.

So, Max ends up with a sequence of ints and it returns the highest of these.

Easy, eh :)
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Glenn Patton14y ago
Thanks for that, it's not that I don't like LINQ it just I've never come up with LINQ solution myself and probably don't really understand it enough to use unguided, need to sit down with it that's all, Cheers thanks for that appears to working! Glenn
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Vulpes14y ago
If you don't like LINQ, then this should also work:

string[] file_Next = Directory.GetFiles(mydocpath, "SV_????.msg");
Array.Sort(file_Next);
string maxFileName = Path.GetFileName(file_Next[file_Next.Length - 1]);
int FileCounter = int.Parse(maxFileName.Substring(3, 4));
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Glenn Patton14y ago
LINQ? again! whenever (if) I get the time there shall be some severe LINQing happening!
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Vulpes14y ago
That line is basically right though you can use the ? wildcard to filter the files returned more accurately.

What I'd do is this - I'm assuming that a four digit number will always be used.

I've used LINQ to get the maximum file number as it's much easier than traditional methods:

using System.Linq;

//....

string[] file_Next = Directory.GetFiles(mydocpath, "SV_????.msg");
int FileCounter = file_Next.Max(file =>
{
file = Path.GetFileName(file);
return int.Parse(file.Substring(3, 4));
});
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Glenn Patton14y ago
Mmm...That appears to be true (I have sat here and had fiddle) so I am sorry to ask this but what would your method be for getting around this problem. I am not so worried about about other files (.msg's) appearing as this is in a sub directory for my code only, I am a little worried about the string[] file_Next = Directory.GetFiles(@mydocpath, "*.msg"); as I got this from a reference book by Microsoft (which was holding a desk with a Linux file server on it up, time to put it back??)
Glenn
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Vulpes14y ago
A couple of points strike me there.

If there are any other files (not fitting your pattern) which have a .msg extension, then they may be being counted.

If there are omissions in the sequence of files fitting your pattern (say sv_0130 is missing), then this will also mess up the counting.

So how are you calculating FileCounter?

If you're just using file_Next.Length, then this might be causing the problem.
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Glenn Patton14y ago
Yes, thats how I'm doing it.

string[] file_Next = Directory.GetFiles(@mydocpath, "*.msg");
int FileTotal = 0;

and once the file data has been set up

StreamWriter sw = new StreamWriter(mydocpath + @"\SV_" + FileNameRecord + ".msg");

dt.ToString("yyyy/MM/dd HH:mm:ss");
FileNameRecord = (FileIDFiller + FileCounter.ToString());
//StreamWriter sw = new StreamWriter(mydocpath + @"\SV_" + FileNameRecord + ".msg");
sw.WriteLine("Test " + FileCounter.ToString()+" "+dt.ToString());
sw.WriteLine(Unit_Reply_Modded);

FileCounter++;

strFileCount = Convert.ToString(FileCounter); ;

sw.Close();

Could something here be causing the problem....
Glenn
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Vulpes14y ago
That suggests to me that the numbering depends on something which you read in every time the application runs. Perhaps you are looking at the highest number of the existing files and then adding one to that?
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Glenn Patton14y ago
The problem I was having yesterday, today the same code that was a problem yesterday is not today. That fills me with fear!
Glenn
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Glenn Patton14y ago
Well that has created a file of zero size, meaning my OS (XPpro) is still clinging to life!
Yup my code is causing the problem (suprise, suprise).
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Vulpes14y ago
Try going into the command prompt, navigate to the folder which is giving you the trouble and type the following two lines in at the prompt:

copy con SV_0216.msg
^Z

To type ^Z, press the Z key while holding down the Ctrl key.

If that succeeds in creating an empty file, then you'll know that the problem lies with your code rather than the OS.
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Glenn Patton14y ago
OK, I was quite prepared to believe I calculating the numbers wrong, but I changed the folder to one higher and could create with no problems up to SV_0160.msg. The problem seem to the folder, if I create a folder and a sub folder C:\Test_Stuff\Sub_Test_Stuff it will create in there up to SV_0215.msg meaning the most obvious issue is not the cause. Equally I was not sure if the extension .msg was causing the problem (Outlook linked .msg files...), now it appears to be a mystery (oh joy what a way to come back from a bank holiday!)

Glenn
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Vulpes14y ago
The most likely explanation is that whilst you think you're creating the string, SV_0133.msg, you're in fact creating SV_0132.msg - perhaps because of a bug in the way you're counting the files.

Years ago, there used to be a limit on the number of files you could have in a root drive under Windows. I'm not sure whether there's a limit now or not, but even if there is I'm sure the OS wouldn't just overwrite an existing file.
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Glenn Patton14y ago
It is a flat file ACSII text!
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Glenn Patton14y ago
=-=-=-=-=-=-=-=-=-=-=-=-=
EDIT
=-=-=-=-=-=-=-=-=-=-=-=-=

It seems it is not a problem other than the directory it is supposed to be!!!
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Suthish Nair14y ago
If you are saving the file information to DB table, then use the Identity coulmn value to update the file name..
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