Redirecting console output in realtime?

[Markus S.]

Hello,

I have a problem with a DOS EXE that is called by a .Net Winforms
application. I need to redirect the console output into a textbox, but
this should happen in real time, so when new output is written to the
redirected StandardOutput-Reader, I want to catch it immediately and
add it the my textbox.

Now, I have tried everything from threads to invokes, but every time i
call the read/readline/readtoend function in the thread, it suspends at
this point. After the process is finished, my thread goes on and the
output is written to the textbox.

Does anybody have an idea how i can make the thread run the entire
time, without stopping after the first access of standardoutput?

I should add that I use VB 2003, so I am not able to use any of the new
2005 classes.

Here are some code snippets:
(the following code lies in an extra class, outside of the GUI)

'Called from the Form when "start"-button is clicked
Public Sub Start()
'See below for exact code of createProcess()
myProc = createProcess()
myProc.Start()

'New Thread for catching the StandardOutput in realtime
myThread = New Threading.Threa d(AddressOf startCatch)
myThread.Name = "ConsoleCatcher "
myThread.IsBack ground = True

myThread.Start( )

End Sub

'Creates a Process with appropriate settings
Private Function createProcess() As Process
Dim objP As New Process
objP.StartInfo. UseShellExecute = False
objP.StartInfo. RedirectStandar dOutput = True
objP.StartInfo. RedirectStandar dError = True
objP.StartInfo. CreateNoWindow = True
objP.StartInfo. WorkingDirector y = Application.Sta rtupPath

objP.StartInfo. FileName = myFile
objP.StartInfo. Arguments = myArgs

Return objP
End Function


'That's what happens in the output-catching function
Private Sub startCatch()
Try
Dim strLine As String

Do While Not myProc Is Nothing
'The Thread stops while executing the line below for the
first time.
'It continues normally after the Process belonging to the
StandardOutput has finished...
strLine = myProc.Standard Output.ReadLine ()
If strLine <> "" And strLine <> Nothing Then

'Event caught by the Form
RaiseEvent ConsoleOut(Me, New
DataReceivedEve ntArgs(strLine) )
End If

Loop

'See if there's anything left
strLine = myReader.ReadTo End
If strLine <> Nothing And strLine <> "" Then
RaiseEvent ConsoleOut(Me, New
DataReceivedEve ntArgs(strLine) )
End If
Catch
End Try

End Sub


Any help is highly appreciated. Thanks alot! :-)

Bye,
Markus

[Herfried K. Wagner [MVP]]

Re: Redirecting console output in realtime?

"Markus S." <sneets@virtual sneets.de> schrieb:[color=blue]
> I have a problem with a DOS EXE that is called by a .Net Winforms
> application. I need to redirect the console output into a textbox, but
> this should happen in real time, so when new output is written to the
> redirected StandardOutput-Reader, I want to catch it immediately and
> add it the my textbox.
>
> Now, I have tried everything from threads to invokes, but every time i
> call the read/readline/readtoend function in the thread, it suspends at
> this point. After the process is finished, my thread goes on and the
> output is written to the textbox.[/color]

<URL:http://www.palmbytes.d e/content/dotnet/console.htm>
<URL:http://dotnet.mvps.org/dotnet/samples/misc/#RedirectConsol e>

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://classicvb.org/petition/>

[Cor Ligthert [MVP]]

Re: Redirecting console output in realtime?

Markus,

Any problem that I show you this sample instead of looking to your code (I
made it in this way now, tested it however changed some things for the page
so watch errors because of that changing).

http://www.windowsformsdatagridhelp.com/default.aspx?ID=1f8f3eaf-27a1-40d7-9e0b-23cab5aa1049

I hope this helps,

Cor

[Markus S.]

Re: Redirecting console output in realtime?

Hi again,

the first example from
http://www.palmbytes.de/content/dotnet/console.htm is almost the same I
did. and it behaves the way my app does :-)

Maybe I have to specify my problem more exactly.

I am writing a .net frontend for cabarc.exe which created cab archives.

now, let's assume I call the exe with a filelist of 20 files. when i
use the standard console output, the screen is updated after every file
(i can watch the progress in real time, as i get a line saying "file x
added to archive"). when i redirect the output and start cabarc, I
won't get a response from standardoutput. readline until the exe has
finished running...
Slowly it makes me belive that this behavior is just the way the
process class works (waiting until the underlying exe-process is
finished and then redirecting the whole bunch of lines in one step)...

or is there any workaround for this maybe?

But thanks already for the help everybody!

[Cor Ligthert [MVP]]

Re: Redirecting console output in realtime?

Markus,

Did you beside that palmbytes sample as well tried the sample I made for
you?

Cor

[WolverineSoft]

Api

Hello Markus,
hope to find someone with the same mine problem ;)

First of all, i want to tell you of i'm searching for an answer for a long , very long time....

I tryed, like you, to use Cabarc, but my first purpose is to use the redirection in realtime with GoldenHawk DAO burning technology...

As you know most simple software is able to send realtime output to the VB redirector. Most people try to help us in this wrong way. They don't know the existing of some particular dos.exe softwares which not show the output immediately, or don't show it at all untill the end...(cabarc is a valid example)

Please sorry for my bad english, i'm italian...

Anyway i coded a special software which is able to do it...

Simple: i builded a Console application which launch a DOS.exe software and read its output realtime by directly reading the screen.....ther e are some useful APIs to do it.... and it works 100%..(also in hidden mode)

My software SubSonic Music Burner does it perfectly...

The only issue is on how to pass data beetween the Console Application 8Not the EXE, but the Console application i builded to read the EXE output) and the main visual basic project, the form....
I'm using right now the windows registry, but i hope to really be able to find a better way, because this way is frustrating and a little slow....

My email is stefano@subsoni c.it and you can find me here if you need the code. in exchange i hope you will let me know if you will find a real way to get the output realtime with the simple standard redirection....

Please Note, i found the new and awesome new feature within visual basic 2005 express which read data asyncronously from the output. This is cool but unfortunately the unable to get it realtime remain inalterated :D ...
Another cool info is of the StandarError is able to show it realtime....i think it have a different PIPE buffer size...Anyway at this time only the LAME Mp3 tools is using the standard error to show realtime the progress...

I hope i wiil able to help you exactly like you will be able to help me in the future...

Stefano