Re: How can I........? - Visual Basic Discussion Boards

800XL24-May-04 5:59

24-May-04 5:59

Hello
I have created a class which starts a new thread to listen for a connection on a tcp port, which seems to work very well. However, I have a problem that I do not want the background thread to allow the connection if the main thread is busy processing.

Does anyone know if there is a way I can check if the main thread in not responsive from a background thread? I have tried threadstate and isalive, but the thread is still running and alive... just busy.

Thanks

Atari 800XL

Re: Multithreading Help

Dave Kreskowiak24-May-04 7:11

Dave Kreskowiak

24-May-04 7:11

Wouldn't that, by definition, defeat the purpose of a multithreaded app? I mean, you start other threads to handle tasks independent of the main thread so the main thread can go on it's merry way and do something else...

Anyway, I think this isn't as easy as it would sound, because you can't call a method/property on either thread that returns this state because the calling thread would be blocked waiting for the other thread to actually free up and execute your call... I think...

You could look into the Application.Idle event, but that will only fire when your code starts to Idle. There is no event that fires when your code comes OUT of idle, so there is no way to determine when your app is busy.

RageInTheMachine9532
"...a pungent, gastly, stinky piece of cheese!" -- The Roaming Gnome

Re: Multithreading Help

800XL24-May-04 23:32

800XL

24-May-04 23:32

I aggree it is quite a strange use of multi-threading, but I need to monitor remotely if the program is still responding.

I had a look at the application.idle event and think this could work, the problem is I can't hook up to this event from the class as system.windows.forms.application is not available

Re: Multithreading Help

Dave Kreskowiak25-May-04 0:24

Dave Kreskowiak

25-May-04 0:24

The Application object isn't from Forms. It also doesn't fire an Event that can be used just like any other... I haven't figured how to use it yet, and frankly, don't have the time right now.

What do you mean by Remotely? From another machine? You original post said from a seperate thread. So which is it?

Does this app that your monitoring have a GUI user interface?
You could use the Process class to see if the user interface is still responding, just get the processes on a remote machine using Process.GetProcessByName(machinename, processname). Then check the Process.Responding() property to see if the GUI is still responding. If not, you could end the process using the Process.Kill() method.

RageInTheMachine9532
"...a pungent, gastly, stinky piece of cheese!" -- The Roaming Gnome

Re: Multithreading Help

800XL25-May-04 0:57

800XL

25-May-04 0:57

Yeah I wasn't very clear, but what I was attempting to do was monitor remotely using a socket to find out if my program was still responding, but I was getting into trouble because the socket listener was running in a seperate thread. So even though the main thread had hung, my background thread was quite happily telling me everything was ok!

This Process.GetProcessByName is exactly what I needed, no need to bother with sockets or threads at all... superb, thanks!

By the way I managed to access the Application.Idle event by adding a reference to System.Windows.Forms in my class library, then I used the following code to check if the calling thread was idle.

AddHandler System.Windows.Forms.Application.Idle, AddressOf Idle_app<br />
<br />
    Private Sub Idle_app(ByVal sender As Object, ByVal e As System.EventArgs)<br />
        iIdleTime = 0<br />
<br />
    End Sub<br />
<br />

Re: Multithreading Help

800XL26-May-04 1:19

800XL

26-May-04 1:19

Found one slight problem with the Process.GetProcessByName, running it against a remote machine returns a System.NotSupportedException with the message

Feature is not supported for remote machines.

How can I........?

Night_Soul24-May-04 2:37

Night_Soul

24-May-04 2:37

execute a file in automathic mode using VB.net?

Now I explain myself better.......

I should make run the file xxx. exe in automatic during the execution of a program.........making this in DOS I would do:

C:\> cd C:\WINNT\ServicePackFiles\i386

C:\WINNT\ServicePackFiles\i386>msinfo32.exe /report FILE_NAME.txt /categories

Can I do this two simple operations whith vb??

Please Answer me ASAP....it's very important....

Thanks All. Wink | ;)

Night Soul!!!

Re: How can I........?

Dave Kreskowiak24-May-04 3:22

Dave Kreskowiak

24-May-04 3:22

What? Your post doesn't make any sense at all. What do you mean by 'automatic'?

Are you asking how you can launch two applications (.EXE's) if you double-click one of
them? Are you asking how to launch another application from inside your application?

In VB.NET, you'd use the Process and ProcessStartInfo classes to launch an external application.

RageInTheMachine9532
"...a pungent, gastly, stinky piece of cheese!" -- The Roaming Gnome

Re: How can I........?

Night_Soul24-May-04 4:45

Night_Soul

24-May-04 4:45

first of all thanks for the reply...

maybe I express myself bad.

I want to create a subroutine or a function that when it run make this:

C:\> cd C:\WINNT\ServicePackFiles\i386

C:\WINNT\ServicePackFiles\i386>msinfo32.exe /report FILE_NAME.txt /categories

is it possible?

It hope to be explained myself better this time..

Thanks of the help. Wink | ;)

Night Soul!!!

Re: How can I........?

Dave Kreskowiak24-May-04 5:00

Dave Kreskowiak

24-May-04 5:00

Make what? Are you talking about running an external application?

Easy enough?

Dim newProcess As New Process
newProcess.Start(C:\WINNT\ServicePackFiles\i386\msinfo32.exe", "/report FILE_NAME.txt /catagories")

RageInTheMachine9532
"...a pungent, gastly, stinky piece of cheese!" -- The Roaming Gnome

Re: How can I........?

Night_Soul24-May-04 22:20

Night_Soul

24-May-04 22:20

IT WORK!!!

Thanks a lot.;););)

(and sorry for not perfect my English... Blush | :O

)

Night Soul!!!

Audio Tool

Night_Soul24-May-04 0:00

Night_Soul

24-May-04 0:00

Hi all!!!

first of all I want to greet all of you...this is my first thread here!!! Smile | :)

I need your help because i'm tring to do a program that on keypress of a button (in the keyboard) will activate the "mute on"....is it possible?

thanks for your attention....

Night Soul!!!

Re: Audio Tool

Dave Kreskowiak24-May-04 3:18

Dave Kreskowiak

24-May-04 3:18

This is possible. You'd have to write either a keyboardhook or a message filter that looks for the keypress you want, then you'd call the multimedia functions that will mute the sound. This seeming simple part will be extraordinarily difficult if your not familiar with the Multimedia SDK and P/Invoking API functions.

Multimedia SDK Docs[^]

RageInTheMachine9532
"...a pungent, gastly, stinky piece of cheese!" -- The Roaming Gnome

multi user application

Ganesh4u23-May-04 23:11

Ganesh4u

23-May-04 23:11

i know how to develop single user(desktop) database application using ado.How i can make it multi user(more than one computer) in visual basic 6.0 and access/oracle as backend.

Re: multi user application

Dave Kreskowiak24-May-04 3:09

Dave Kreskowiak

24-May-04 3:09

It's not much different than a single user app. The database backend should handle the bulk of the concurrency and your user side shouldn't know (or care) about any other instance running on another machine.

What do you mean by "Access/Oracle" backend? Are you using and Access database and an intermediary to an Oracle database? Why the Access part?

RageInTheMachine9532
"...a pungent, gastly, stinky piece of cheese!" -- The Roaming Gnome

Unicode Converting

Pugman81223-May-04 23:02

Pugman812

23-May-04 23:02

I am making a blowfish cryptography program in vb .NET and i have run into a point where i have to convert for unicode. I tried using the StrConv() function but it no long support vbFromUnicode enum. I can convert to unicode but i just need to convert back in .Net. The code that i am using in 6.0 is

Key() = StrConv(New_Value, vbFromUnicode)

Any help with this would be great.

Re: Unicode Converting

Dave Kreskowiak24-May-04 3:01

Dave Kreskowiak

24-May-04 3:01

You might want to replace 'vbFromUnicode' with 'VbStrConv.Wide' in the VB.NET code.

RageInTheMachine9532
"...a pungent, gastly, stinky piece of cheese!" -- The Roaming Gnome

Hardware Detection

macjules23-May-04 22:07

macjules

23-May-04 22:07

Hi guys!!!

Im new to VB.NET, and im having some difficulty writing a code that displays all the hardware setting and specifications, presumably currently installed into a computer....What should I do?? =(

Your help will greatly be appreciated!!!

Thanks,
jules

Re: Hardware Detection

Dave Kreskowiak24-May-04 2:50

Dave Kreskowiak

24-May-04 2:50

majulose wrote:
What should I do??

You never mentioned what you problem was. Try posting an actual question...

RageInTheMachine9532
"...a pungent, gastly, stinky piece of cheese!" -- The Roaming Gnome

little-endian/big-endian

fuel2run23-May-04 21:51

fuel2run

23-May-04 21:51

hi there,

i'm having big trouble in reading a binary file that has some values in little-endian encoding and some other in big-endian encoding in the header.
can someone explain how to read the header retreaving those values?

thanks in advance.
fuel2run

Re: little-endian/big-endian

Dave Kreskowiak24-May-04 2:57

Dave Kreskowiak

24-May-04 2:57

fuel2run wrote:
a binary file that has some values in little-endian encoding and some other in big-endian encoding

WHAT?? Very strange...
But the fields that are encoded backwards would have to be read into a byte array and you'll have to write the code to reverse the byte order and then do some simple math to get the value back out.

byte0 | byte1 | byte2 | byte3

Gets reversed to:
byte3 | byte2 | byte1 | byte0

Do the math:
Value = (Byte3 << 24) + (Byte2 << 16) + (Byte1 << 8) + Byte0

Of course, this is subject to exactly how the bytes are really stores and what the value is supposed to be. You COULD have something like this if the values were stored WORD reversed instead of BYTE:

byte0 | byte1 | byte2 | byte3

Should be:
byte2 | byte3 | byte 0 | byte 1

It all depends on the system that wrote the file...

RageInTheMachine9532
"...a pungent, gastly, stinky piece of cheese!" -- The Roaming Gnome

Re: little-endian/big-endian

fuel2run24-May-04 4:31

fuel2run

24-May-04 4:31

thanks Dave,

i have to read some "int32" (in vb.net) and i know "where they are" , could you explain the simple math you wrote? i'm not familiar with that sintax (Byte3 << 24 ?)

a win system wrote the file,it is an esri shape file.

thank you
fuel2run

Re: little-endian/big-endian

Dave Kreskowiak24-May-04 4:51

Dave Kreskowiak

24-May-04 4:51

The << and >> operators are bit shift operators available in VB.NET 2003. They don't exist in 2002. All they do is shift a value a specificed number of bits in that direction. So if you, int a UInt32 had the value &HFF (decimal 255), it would look like this:

00000000|00000000|00000000|11111111

Shifting the value 24 bits to the left, it would now look like this:

11111111|00000000|00000000|00000000

And it's value would then be &HFF000000 (decimal 4,278,190,080).

You could accomplish the same shift by multiplying the value by 2^24.

RageInTheMachine9532
"...a pungent, gastly, stinky piece of cheese!" -- The Roaming Gnome

Re: little-endian/big-endian

fuel2run24-May-04 6:49

fuel2run

24-May-04 6:49

i'll try as soon as possible, you've been crystal clear

thank you!
fuel2run

Re: little-endian/big-endian

fuel2run1-Jun-04 21:57

fuel2run

1-Jun-04 21:57

it works fine Dave!

it's the very first time i read binary data.
many thanks!
fuel2run

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