Re: how to capture logfile changes into a text box - C# Discussion Boards

how to capture logfile changes into a text box

Rafferty Uy26-Dec-06 22:58

26-Dec-06 22:58

Hello,

I am trying to capture changes in a logfile (which is outputed by an external executable) and show them on a text box. Because the logfile updates from time to time, I cannot simply do a while ((line = reader.ReadLine()) != null). Any suggestions on how I can capture the changes in the log file? The assumption is that the log file will just keep appending text and never get deleted. Capturing the output will end when the external .exe ends (finishes running).

Please help.

Thanks!
~Rafferty

Re: how to capture logfile changes into a text box

Marek Grzenkowicz27-Dec-06 0:47

Marek Grzenkowicz

27-Dec-06 0:47

FileSystemWatcher may help.

Use FileSystemWatcher to watch for changes in a specified directory. You can watch for changes in files and subdirectories of the specified directory. You can create a component to watch files on a local computer, a network drive, or a remote computer.

Re: how to capture logfile changes into a text box

PIEBALDconsult27-Dec-06 3:29

PIEBALDconsult

27-Dec-06 3:29

I do something like that.

I keep track of the position of the last byte I read from the file.
On each cycle I:

open the file
seek to the last position
read to the end
save the new position
close the file

(This is done by a service that cycles every ten seconds and reads the log of a third-party application.)

You could also keep the file open:

open the file
while (someTest)
{
if ( filePosition < fileLength )
{
read to end
}
else
{
sleep
}
}
close the file

Re: how to capture logfile changes into a text box

Luc Pattyn27-Dec-06 7:16

Luc Pattyn

27-Dec-06 7:16

Interesting idea.
But isnt there some risk that, while your code reads the new data from
the tail of the file, the original program is unable to append to it ??

Smile | :)

Luc Pattyn

Re: how to capture logfile changes into a text box

Rafferty Uy27-Dec-06 15:47

Rafferty Uy

27-Dec-06 15:47

Luc is right, I am getting an IOException when I open the log file using StreamReader because the external process is still appending to the log file. Any suggestions on how I can just read the file using read access which still allows other processes to write to it? I tried using FileStream but I just can't figure out how to use the Read(...) method, how do you convert byte[] to a string?

Thank you for your help,
~Rafferty

Re: how to capture logfile changes into a text box

Luc Pattyn27-Dec-06 16:48

Luc Pattyn

27-Dec-06 16:48

Sorry, I actually meant the other risk, where the log producer might
be hampered by the log consumer doing its thing.

The log consumer can always react on an IOException and come back
later to retry, but the log producer (over which we may not have control)
should never be hampered by the log consumer(s) and I am not sure
that is the case in the proposed setup.

Smile | :)

Luc Pattyn

Re: how to capture logfile changes into a text box

Rafferty Uy27-Dec-06 18:50

Rafferty Uy

27-Dec-06 18:50

oh.. yes that is the case, i do not have control on the log producer. Can you propose a solution on how i can read the log? Here is how I tried to do it but it stopped the log producer from executing (so I guess it was hampered as you just said).

<br />
using ( FileStream fileStream<br />
  = new FileStream(e.FullPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite ) )<br />
{<br />
  fileStream.Seek(_logFileLastReadPosition, SeekOrigin.Begin);<br />
  TextReader reader = new StreamReader(fileStream);<br />
<br />
  string line;<br />
  while ( (line = reader.ReadLine()) != null )<br />
  {<br />
    PerformOutputAppended(this, new OutputEventArgs(line));<br />
    _logFileLastReadPosition += line.Length;<br />
  }<br />
          <br />
  reader.Close();<br />
  fileStream.Close();<br />
}<br />

the code above is executed during a FileSystemWatcher Changed event, e.FullPath contains the full path of the log file. PerformOutputAppended(...) is the method which appends the string into the UI textbox.

I'm not sure if i'm doing things correctly as I am not familiar with these kind of behavior.

Thanks for your help,
~Rafferty

Re: how to capture logfile changes into a text box

Luc Pattyn28-Dec-06 5:00

Luc Pattyn

28-Dec-06 5:00

Hi Rafferty,

I don't have a general solution available, so I did some experiments.

I have one process that periodically (100msec) writes a string to a file;
my writer code reopens the file for every write access
(with a single open, a reader would be unable to access the file at all):

private void output(string s) {
	try {
		StreamWriter sw=new StreamWriter(fileSpec, true); // append !
		sw.WriteLine(s);
		sw.Close();
	} catch (Exception exc) {
		timelog(exc.Message);
	}
}

I have another process that periodically (but at a lower frequency, 1sec) tries
to read one or more lines; the code is similar to yours.
(assume seek is zero and delay is false):

private void input() {
	try {
		StreamReader sr=new StreamReader(fileSpec);
		sr.BaseStream.Position=seek;
		if (delay) Thread.Sleep(1000);	// try to block producer !
		while((string s=sr.ReadLine())!=null) {
			log("line "+line+": "+s); // process the input data
			seek=sr.BaseStream.Position;
		}
		sr.Close();
	} catch (Exception exc) {
		timelog(exc.Message);
	}
}

This duo typically behaves well, I guess because the reader is simple enough
so it can do its job without a task reschedule, so the writer never is active
while the reader has file access.

But when I set delay true (reader keeping file accessed while relinquishing CPU), the writer starts to fail with "cannot access file", exactly as I was expecting.

I am still looking for a general solution; so far I would say the reader should
collect new data and avoid operations that take time or may relinquish the CPU.
But if the OS, for whatever reason, interrupts the input method and reactivates
the writer, things will go wrong there.

Smile | :)

Luc Pattyn

Re: how to capture logfile changes into a text box

Rafferty Uy28-Dec-06 13:47

Rafferty Uy

28-Dec-06 13:47

Hello Luc,

Thank you so much for your help. I was able to figure out what to do, the code I posted above was almost correct, I just forgot to set my processStartInfo.RedirectStandardOutput to false. Here's some fixes to the code I posted above:

<br />
using ( FileStream fileStream<br />
  = new FileStream(e.FullPath, FileMode.Open, FileAccess.Read, FileShare.ReadWrite) )  // setting the FileShare to ReadWrite allows the logger to keep on writing to the text file while this reads the current output.<br />
{<br />
  fileStream.Seek(_logFileLastReadPosition, SeekOrigin.Begin);<br />
<br />
  TextReader reader = new StreamReader(fileStream);<br />
<br />
  string line;<br />
  while ( (line = reader.ReadLine()) != null )<br />
  {<br />
    PerformOutputAppended(this, new OutputEventArgs(line));<br />
  }<br />
<br />
  _logFileLastReadPosition = fileStream.Seek(0, SeekOrigin.End);<br />
          <br />
  reader.Close();<br />
  fileStream.Close();<br />
}<br />

Comments/suggestions greatly appreciated. But this is already serving my needs.

Thanks again Luc! Big Grin | :-D

~Rafferty

Using a navigator panel

quiteSmart26-Dec-06 22:56

quiteSmart

26-Dec-06 22:56

hi all,

I am trying to develop an application that contains a navigator panel. the panel is supposed to have a small size of width only 7 on the loading process.

when the mouse comes over the panel wich is this thin layer of width 7 the panel should grow to be in its normal size.

and when the mouse leaves the panel the panel should shrink again to be of width 7.

It is working very fine (using the mouse enter and mouse leave events) but only when the panel is empty and does not contin any button.

but when i fill it with buttons it is not working at all.

I think it is because when the button is added to the panel it takes part of the visible part of the panel so it will not through the events of mouse enter.

I tried to make the buttons' visible property to false when the panel is in the shrinking mode but this didn't give any result to.

i tried to work on the mouse enter and mouse leave events of the buttons and this didn't work too.

did anybody face a problem like this before.

if so plz give me a solution.

i will keep trying to work it out.
if i find the solution before u i will tell u about it.

thanks in advance,

MDIchild form goes behind the panel

thunaivanu26-Dec-06 22:16

thunaivanu

26-Dec-06 22:16

Hi friends,

I have a panel in the MDI form and there are some controls in the panel .When I open MDIChild forms ,the forms go behind the panel.
I tried forms.BringtoFront()and panel.SendtoBack().But nothing works.
Then I set setchildIndex of panel to 0 but ,no improvement.

Is there any way to keep the panel always behind all the forms ?

If anybody can help me on this,please..

Thanks

Re: MDIchild form goes behind the panel

il_masacratore27-Dec-06 2:41

il_masacratore

27-Dec-06 2:41

Hello,

I think that not. The MDIChilds will ever go behind the panel. There are two ways of solving this:

- Docking the panel of the MDIParent on top(for example, if is smaller than the main form).

- Showing off the panel of the parent when MDIChilds are added(if the size is the same that the form).

Re: According to your suggestions

thunaivanu27-Dec-06 17:27

thunaivanu

27-Dec-06 17:27

I tried out your suggestions.I docked the panel on top of MDIForm,but then the child form started coming under the panel where I require it to come above the panel.

Sorry I didn't understand your second suggestion.If you intented to say to apply panel.show().It's always on that mode it does appear.I want child form.Show() happen effectively.

Can any one give an idea......?

ravichandratbv26-Dec-06 21:56

ravichandratbv

26-Dec-06 21:56

i have to do free from select operation in ms paint..can any one give an idea..
I did drawing the rectangle by taking maximum point and minimum point after that how to fill regions ..and how to get the path... Confused | :confused:

ravi

Voice Chat

AB777126-Dec-06 21:52

AB7771

26-Dec-06 21:52

Hi all,
Can anyone tell me how to implement Voice Chat in C# .Net??

Thanks & Regards,
Pramod
"Everyone is a genius at least once a year"

How do I call a C# DLL Using Visual Studio 2005 ( C# Code)

Peter Usinga26-Dec-06 21:14

Peter Usinga

26-Dec-06 21:14

None

Re: How do I call a C# DLL Using Visual Studio 2005 ( C# Code)

Colin Angus Mackay27-Dec-06 0:22

Colin Angus Mackay

27-Dec-06 0:22

wrote:
None

What do you want help with? You'll have to supply more information than "none".

Upcoming Scottish Developers events:
* Glasgow: Tell us what you want to see in 2007

My: Website | Blog | Photos

Re: How do I call a C# DLL Using Visual Studio 2005 ( C# Code)

ed^nrgc28-Dec-06 6:35

ed^nrgc

28-Dec-06 6:35

???

Images + Propertygrid

Tanuja12326-Dec-06 19:51

Tanuja123

26-Dec-06 19:51

I want to display 3 images in a single row of propertygrid.

Ex: Fruit - > |Image1 |Image2 |Image3 |

Hw can i display like that..

JPEG 2000

MozhdehQeraati26-Dec-06 19:39

MozhdehQeraati

26-Dec-06 19:39

I have some questions about displaying jpeg 2000 files in C#.NET. It means I have a binary file which is in JPEG 2000 format. I want to display it in a picture box. Does C#.NET support it or not? Is any conversion needed?
Thanks in advance.

???? Error in crystal Report Build by using Command SQL in c#.net ??

jaganil26-Dec-06 18:42

jaganil

26-Dec-06 18:42

Hi All
Plz Help me
I am new to crystal Report and C#.net
Confused | :confused:

In Last Couple of Day I am Batting with Following Problem , and Solution of this priblem is important for me

I am created crystal Report By using Command SQl ( by selecting ADD Command on the Database Expert-> Create new connection -> Add Command

I have two problem

1) If I Eable the Logon Promt (i.e EnableDatabaseLogonPrompt ="true" )

then following promt is display Before the Report View and Asked for the server passward if i enter passward then Report is Display otherwise not ( It's Happen 1 st time when aplication is run or Session is Exprire) the promt is given below in bold letter

The report you requested requires further information.

___________________________________________________________________

SERVER
Server name: Server
Database name: ERPDB
User name: sa
Password: --------
Use Integrated Security

2) If I disable the Logon promt (i.e EnableDatabaseLogonPrompt ="false")

then following Error Message is Display and Report Can not Display

Logon failed. Details: ADO Error Code: 0x Source: Microsoft OLE DB Provider for SQL Server Description: Login failed for user 'sa'. SQL State: 42000 Native Error: Error in File C:\DOCUME~1\ADMINI~1\LOCALS~1\Temp\SalaryReport {4244492D-0548-4110-AF32-9A9E5066CD0E}.rpt: Unable to connect: incorrect log on parameters.
Rose | [Rose]

My Actual problem to Display the Report Without Asking Server Passward to User Because User Don't Know the Server Passward

Smile | :)

Please any one Help me

Rose | [Rose]

Thanks for Your Time

Smile | :)

Anil Jagdale

Re: ???? Error in crystal Report Build by using Command SQL in c#.net ??

Tarakeshwar Reddy26-Dec-06 19:29

Tarakeshwar Reddy

26-Dec-06 19:29

Dont keep posting the SAME QUESTION again and again. If someone knew the answer they would have provided you with it.

Tarakeshwar Reddy
MCP, CCIE Q(R&S)

Selection, as if it were text. [modified]

Captain See Sharp26-Dec-06 15:58

Captain See Sharp

26-Dec-06 15:58

I am attempting to create a more efficient way to select data(like text). Before I used an index to the data that was stored in an array. I would have a separate collection or array that held the indexes of the data in another array. Each index in the "selection array" was selected. I think I have made a more efficient way to do that using two longs per selection, it does not matter how large the selection is, it will always be two longs.

void SelectData(long start, long end)
{
  _selected.Add(new Range(start, end));
  if (_selected.Count > 1)
    RemoveRangeRedundancies();
}

void RemoveRangeRedundancies()
{
  foreach (Range rr in _selected)
  {
    foreach (Range r in _selected)
    {
      if (rr == r) continue;

      if (rr.MinValue >= r.MinValue && rr.MaxValue <= r.MaxValue)  //selection completely inside an already selected range of data.
      {
        _selected.Remove(rr);
        continue;
      }

      if (rr.MinValue <= r.MinValue && rr.MaxValue >= r.MaxValue) //selection bigger on both or one rr.MaxValue
      {
        _selected.Remove(r);
        continue;
      }

      //selection bigger or connected to the left (join)
      if (rr.MinValue < r.MinValue && (rr.MaxValue >= r.MinValue - 1) && rr.MaxValue <= r.MaxValue)
      {
        Range newRange = new Range(rr.MinValue, r.MaxValue);
        _selected.Remove(rr);
        _selected.Remove(r);
        _selected.Add(newRange);
        continue;
      }

      //selection bigger or connected to the right (join)
      if (rr.MinValue >= r.MinValue && (rr.MinValue <= r.MaxValue + 1) && rr.MaxValue > r.MaxValue)
      {
        Range newRange = new Range(r.MinValue, rr.MaxValue);
        _selected.Remove(rr);
        _selected.Remove(r);
        _selected.Add(newRange);
        continue;
      }
    }
  }
}

Do you think that is a good design?

-- modified at 23:36 Tuesday 26th December, 2006

-- modified at 23:40 Tuesday 26th December, 2006

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Collection.IndexOf Method Question?

haz1326-Dec-06 13:46

haz13

26-Dec-06 13:46

I can't seem to get my head around the following.

My Frequency class has two fields Data1 and Data2.

public static List<frequency> ColourFreqCollection = new List<frequency>();

ColourFreqCollection.Add(new Frequency(1,2));
ColourFreqCollection.Add(new Frequency(3,2));etc

Is it possible to now use the IndexOf method to look in the Frequency objects Data1 field and return the index if a particular number exists?

ColourFreqCollection.IndexOf(don't know what to put here! -look in object data1 field and return index if true);

Else what would be the best thing to do?

Thanks in advance for your help.

Haz

Re: Collection.IndexOf Method Question?

Christian Graus26-Dec-06 15:04

Christian Graus

26-Dec-06 15:04

ColourFreqCollection.IndexOf(new Frequency(1,2));

That's all you can do, you don't have a reference to the object you're looking for.

Christian Graus - Microsoft MVP - C++
Metal Musings - Rex and my new metal blog

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