.NET (Core and Framework)

13-Feb-03 7:44

I'm trying to access an MS Access database that exists on a Novell network drive from within a Windows service. I keep getting the following error:

'\\mcgs1\mcgv3\Dsys2002\prudent\copyprud.mdb' is not a valid path.  Make sure that the path name is<br/>spelled correctly and that you are connected to the server on which the file resides.

This IS a valid path, because when I use the exact same path in a .vbs file on my local drive, it connects fine.

Here's the relavent code:

'Conn is a OleDbConnection object
'Doc is a config file, and the PrudDB element contains the above network path
Conn = New OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & _
                Doc.DocumentElement.SelectSingleNode("PrudDB").InnerText & "; User ID=admin; Password=")
Conn.Open()

It's when I call the Conn.Open that the error is thrown. Any ideas?

Thanks in advance.

Kyosa Jamie Nordmeyer - Cho Dan
Portland, Oregon, USA

Stephane Rodriguez.13-Feb-03 7:50

13-Feb-03 7:50

Do you know the difference between \ and \\ ?

Jamie Nordmeyer13-Feb-03 7:57

13-Feb-03 7:57

Um. Yes. I did use '\\' at the beginning of my network path to the database. I tried using a drive mapping as well, and got the same results.

Kyosa Jamie Nordmeyer - Cho Dan
Portland, Oregon, USA

leppie14-Feb-03 6:17

leppie

14-Feb-03 6:17

Jamie Nordmeyer wrote:
I did use '\\' at the beginning of my network path to the database.

If you dont add a "@" you will need to escape each \ e.g "\\\\localhost\\sharedpath\\file.mdb" or @"\\localhost\sharedpath\file.mdb" or (if you wanna be ultra cool) "//localhost/sharedpath/file.mdb".

Oh the Friday blues Poke tongue | ;-P

MyDUMeter: a .NET DUMeter clone
"Thats like saying "hahahaha he doesnt know the difference between a cyberneticradioactivenuclothermolopticdimswitch and a biocontainingspherogramotron", but with words you have really never heard of."

Jamie Nordmeyer14-Feb-03 9:36

14-Feb-03 9:36

Thanks for the reply, leppie. Actually, I'm programming in VB.NET, so the escape charectors don't exist, which is unfortunate (whatever moron at Microsoft decided that Microsoft.VisualBasic.vbCrLf was better than \n needs to be shot). The code seems to run fine when it's from a command line app, so I'm gonna try putting the meat of the thing in a command line app, and just have the Service itself spawn it.

Kyosa Jamie Nordmeyer - Cho Dan
Portland, Oregon, USA

Richard Deeming14-Feb-03 0:00

Richard Deeming

14-Feb-03 0:00

You need to set the service to run under a user account with permission to access the file. By default, it will run under the SYSTEM account, which has no permissions on other machines.

"These people looked deep within my soul and assigned me a number based on the order in which I joined." - Homer

Jamie Nordmeyer14-Feb-03 9:20

IP performance counter in .NET

14-Feb-03 9:20

Hey Richard. Thanks for the reply. I've tried running the process under both my name (I have system administrator rights), and as the network admin account itself, both with no success. The code seems to run fine when it's from a command line app, so I'm gonna try putting the meat of the thing in a command line app, and just have the Service itself spawn it.

Kyosa Jamie Nordmeyer - Cho Dan
Portland, Oregon, USA

princedom13-Feb-03 6:37

princedom

13-Feb-03 6:37

Hi,
I have a problem with peformance counters in C#.NET.
What I want to do is get a number of packets just like the number of
send/received packet that can be found in the Status windows, if
you click at the bottom right of your screen to your network
connection icon (the two small in/out screens flashing the network
activity).

The Received Datagrams/sec decription goes like that:
Datagrams Received/sec is the rate, in incidents per second, at
which IP datagrams are received from the interfaces, including those
in error. Datagrams Received/sec is a subset of Datagrams/sec.

But I want PACKETS not RATE. Is there any way I could somehow use
this rate to get packets?

I want to start my application, get the counter data, do somethings,
get the counter again and found the number of packets received
through the use of my application.

I could also do the following: Run my application and while running
it, I can have a Timer in another thread getting the values of the
counter each sec. So each second I pick a value-rate of the
connection, just like the Performance monitor in Administrative
Tools (control panel) works. But even then I don't get packets.

Is there perhaps a calulation I have to do to get this?

Sure there must be a way since the network activity on the Network
Status in the right bottom on Windows can do it.

BTW, I also run into this counter: Network Interface,
counter:Packets Received/sec with the following description:
Packets Received/sec is the rate at which packets are received on
the network interface.

Same here; rate.

Please help me if possible. This has become a nightmare for me.

Thank you,
Stefanos

Multiple UI Threads, One .NET App

jjreilly12-Feb-03 6:00

jjreilly

12-Feb-03 6:00

I submitted the following to the microsoft.public.dotnet.framework.windowsforms newsgroup:

I've seen a number of posts about threads, forms and controls. I
realize that you shouldn't operate directly on a control from a thread that isn't the control's creating UI thread.

What I want to know is this. In the old Win32 days, your application could create multiple what-they-call UI threads. Each thread had a message pump. You could create a window (say your frame window) on one thread, and create a child window on another thread. The messages for each window would be handled in the context of the window's creating thread.

Some posts have said you can't do that in .NET. Well, I did it.
And it sort of worked.

I created a normal C# Win Forms app. I created another thread. This new thread created a couple of controls. The key is that the
framework prevents you from using the controls's and form's Parent
property to properly hook up the window hierarchy. But you can get
the handles to the form and the controls, and you can call the Win32 SetParent API to hook them up. This works and I can handle events in the proper thread context.

I tried it using a PictureBox control and got a strange result. The strange result was that the picture box control "disappeared" if I set the BorderStyle to anything other than None. I mean, if I look for the picture box in Spy++, the window was real gone, man.

I'm hoping to have some uSoft wizard tell me a couple of things.
First, can I really not use the 1.0 framework to have multiple UI
threads, where one UI thread serves child windows of another UI
thread? Second, any idea why my experience with picture box half
worked?

Thanks. Isn't this interesting???

john.

Re: Multiple UI Threads, One .NET App

Stephane Rodriguez.12-Feb-03 8:08

Re: Multiple UI Threads, One .NET App

12-Feb-03 8:08

jjreilly wrote:
any idea why my experience with picture box half
worked?

When the border style is changed, the underlying window is destroyed and recreated (!). Hence the handle in Spy++ vanishes. But the picture box is there again after recreation, with another handle.

Here is the key executed code :

public void set_BorderStyle(BorderStyle value) {
  if (!(Enum.IsDefined(typeof(BorderStyle), value)))
    throw new InvalidEnumArgumentException("value", value, typeof(BorderStyle));
  if (this.borderStyle != value) {
    this.borderStyle = value;
    this.RecreateHandle(); // window is destroyed, and recreated using the CreateParams property
  }
}


protected virtual CreateParams get_CreateParams() {
  CreateParams local0;
  BorderStyle local1;

  local0 = this.CreateParams;
  local1 = this.borderStyle;
  switch (local1 - 1) {
    case 1:
      local0.ExStyle = local0.ExStyle | 512;
      break;
    case 0:
      local0.Style = local0.Style | 8388608;
      break;
  }
  return local0;
}

jjreilly13-Feb-03 6:14

jjreilly

13-Feb-03 6:14

Thanks. That did the trick. How did you find this out?

john.

Checking file changes

Joao Vaz11-Feb-03 0:27

Joao Vaz

11-Feb-03 0:27

I have a ASP.NET application that needs to check for changes on the client side for a file. This file is constantly being changed and I need , that everytime the file is changed to open the file and check for new data to transmit to my ASP.NET app, so what do you advise ?

Building a dotnet service(it's possible wihout com interop ?) that's is constantly checking the file on the filesystem,or using some javascript function using the filesystem object and a timer to check for changes of the file, or some other way ?

Thanks in advance,

Joao Vaz
And if your dream is to care for your family, to put food on the table, to provide them with an education and a good home, then maybe suffering through an endless, pointless, boring job will seem to have purpose. And you will realize how even a rock can change the world, simply by remaining obstinately stationary.-Shog9

Remember just because a good thing comes to an end, doesn't mean that the next one can't be better.-Chris Meech

Stephane Rodriguez.13-Feb-03 8:02

13-Feb-03 8:02

I am not aware of such stuff inside the .NET CLR.

You've got dedicated functions in the WIN32 File I/O APIs, including ReadDirectoryChangesW, etc.

Now this require WIN32 interop.

Adding COM or ActiveX interfaces would allow you to execute it from Javascript code.

Joao Vaz13-Feb-03 20:48

Joao Vaz

13-Feb-03 20:48

.S.Rod. wrote:
I am not aware of such stuff inside the .NET CLR.

You've got dedicated functions in the WIN32 File I/O APIs, including ReadDirectoryChangesW, etc.

Thanks , I resorted to another technique , using win32 api on one client side app , and recording the data on the database on the Server side.

.S.Rod. wrote:
Now this require WIN32 interop.

Oh well, perphaps on the 2nd version, they'll put the rest of the windows api on it (insert dreamer icon here...)

Cheers,Joao Vaz
And if your dream is to care for your family, to put food on the table, to provide them with an education and a good home, then maybe suffering through an endless, pointless, boring job will seem to have purpose. And you will realize how even a rock can change the world, simply by remaining obstinately stationary.-Shog9

Remember just because a good thing comes to an end, doesn't mean that the next one can't be better.-Chris Meech

Giles21-Feb-03 3:59

Giles

21-Feb-03 3:59

This class implements the equivelent Win API calls to monitor a file, or change in a directory.

System.IO.FileSystemWatcher

Quote from a clever bloke :

"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones." - Albert Einstein

Stephane Rodriguez.22-Feb-03 0:44

22-Feb-03 0:44

Yo!

Giles23-Feb-03 5:17

Giles

23-Feb-03 5:17

I'm guessing that the kitchen sink is in there somewhere. The .NET class lib seems to have everything, its just a case of finding it. Big Grin | :-D

Quote from a clever bloke :

"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones." - Albert Einstein

Stephane Rodriguez.23-Feb-03 5:25

23-Feb-03 5:25

What we are lacking is a Find option in Anakrino! Wink | ;)

(unfortunately, I have tried to recompile this masterpiece but couldn't download everything required to do so).

Giles21-Feb-03 3:58

Giles

21-Feb-03 3:58

Could have a look at System.IO.FileSystemWatcher

Quote from a clever bloke :

"I know not with what weapons World War III will be fought, but World War IV will be fought with sticks and stones." - Albert Einstein