Visual Basic

How to Free a USB port on VB.NET

20-Jan-04 19:17

What your looking for is in this[^] post. Or, if your using VB.NET, you can use Process.Start and Process.StartInfo to do the same thing. Docs on that can be found here[^].

RageInTheMachine9532

Printer Handshake

Ankwa20-Jan-04 11:45

Ankwa

20-Jan-04 11:45

I have been trying to monitor the handshake (signal) from
a printer for each page it printed but i have not been
able to do so. Can any out there help me.

Re: Printer Handshake

Duncan Edwards Jones20-Jan-04 12:12

Duncan Edwards Jones

20-Jan-04 12:12

This article should give you a start..

'--8<------------------------
Ex Datis:
Duncan Jones
Merrion Computing Ltd

elRaptor20-Jan-04 5:48

elRaptor

20-Jan-04 5:48

Hello All:
I'm using an SDK from a device that uses the USB to communicate in the SDK theres is a function that Initializes the port but there is no function or method to free the port, I already try to contact the vendor but I am not having any responce so if someone can helpme whit this, I will very tankful.

JA

Dave Kreskowiak20-Jan-04 18:50

20-Jan-04 18:50

If there isn't a function to Close/Release/Free the port, then your going to have to contact the manufacturer and find out why and what should be done. Another possibility is searching for any sample code, either in the docs for the SDK or on the web, that shows what should be used. But, as with any SDK, what the procedures are and what function names are used depends ENTIRELY on the SDK and the device your using.

RageInTheMachine9532

elRaptor21-Jan-04 5:51

elRaptor

21-Jan-04 5:51

Thanks for your response, I have other question, when I exit the application the port, becomes available, is there a way to close this reference in the application?, or in the main form ?(This is were I'am using this device).

Javier Ayala

Dave Kreskowiak21-Jan-04 6:33

21-Jan-04 6:33

The port becomes available because when your app quits, it releases its resources. This is apparently causing the API to close the port it has open. Once again, it's all in the SDK, there is no standard method of talking to all devices when using an SDK. It MUST be done through calls into the SDK. But if they are not documented, your best bet is the manufacturer.

RageInTheMachine9532

elRaptor22-Jan-04 7:05

elRaptor

22-Jan-04 7:05

Tanks, I already contact the vendor of the device and It toll me that It doesnt have this method, so I thing I am going to try a low level approach, what you thing?

JA

Dave Kreskowiak22-Jan-04 7:31

KeyBinding to Office Add-In

22-Jan-04 7:31

Probably possible, but if your SDK doesn't have to functionality to close a port that it opens, be prepared for a crash when you close the port, but not have the SDK release its resources.

RageInTheMachine9532

JohnWhyte20-Jan-04 4:31

JohnWhyte

20-Jan-04 4:31

I am in the process of writing an Add-In for MS Office XP in MS VB.NET. So far, it amends the office commandbars to add an MsoPopup with two MsoButtons. My next step is to get the events for these two MsoButtons associated with a keycode shortcut; i.e., ALT + L.

I cannot seem to find any information on how this could be achieved. I have looked at the KeyBindings collection in Office, but don't see a way to attach the keycodes to the addin.

Any help gratefully accepted.

John

MDI problem

Anonymous20-Jan-04 1:24

Anonymous

20-Jan-04 1:24

Hi
I have a MDI form where i want to display a mdi child. but i want this child to behave like 'modal()' so the user can't get out the form when it is not completed correctly.
When i import a dialog in the project and form.show it after pressing a menu item in the mdi parent ... then the dialog is only shown when i minimize the mdi parent.
What's the problem here? :s

And another little thing
I dont' seem to find a method for deleting an entry in a listview.

You guys can help?

Greetings
Jens

jimpar20-Jan-04 3:46

jimpar

20-Jan-04 3:46

Remove listitem:

ListView1.ListItems.Remove(lngI)

As for the form:

The QueryUnload event has a second parameter called
UnloadMode. By testing this mode, the program will know what is causing
the form to unload. Then you can decide what you want to do, etc

These are the constants and a brief explanation:

Select Case UnloadMode
Case vbFormControlMenu
'The "X" button or the "Close" menu
'from the form's System menu.
Case vbFormCode
'The Unload statement is called from code.
Case vbAppWindows
'Windows is shutting down.
Case vbAppTaskManager
'The Task Manager is closing the app.
Case vbFormMDIForm
'The form is an MDI child and the
'MDI form is closing.
Case vbFormOwner
'The form is closing because its
'owner is closing.
End Select

"Since we don't know where we're going, we have to stick together in case someone gets there." - Ken Kesey 1935 - 2001

JensB20-Jan-04 20:27

JensB

20-Jan-04 20:27

Hi
Thanks for the reply.
About the form i really meant ... When i want to show a form within an MDI parent (the form has property MDI child: false)... Then that form is not shown within the MDI but apart. I want to be able to show the form nice in the MDI parent without making it MDI child. Because i want to be able to 'DoModal()' the form.

I hope you understand my problem :x

Greetings
Jens

gpa200020-Jan-04 21:38

gpa2000

20-Jan-04 21:38

You can solve this problem programmatically using the mouseover event. When the mouse escapes the form: put it back on the form. As for the form itself, when you move the non MDI form reset the left and top properties to keep the non mdi form within the MDI form. Hope this helps.

Grtz Guus

Anonymous20-Jan-04 22:18

Anonymous

20-Jan-04 22:18

Well, i don't move the form myself ... I just show the form that has to be displayed within the MDI parent itself. So it has to behave like an MDI child but it needs to be displayed modally.

I'll explain situation. I have a menu in the MDI parent .. When i click a menu option .. i want a form to display that is not mdi child. So the form is not shown within the mdi child, but minimised.

Because i don't know well what you meant

Greetings
Jens

Locking files in VB6

steff kamush19-Jan-04 23:48

19-Jan-04 23:48

How do lock a file in VB6 without hardcoding to append a .lock ext to the file name?

How do i unlock? Pls help

Re: Locking files in VB6

Dave Kreskowiak20-Jan-04 8:08

20-Jan-04 8:08

What do you mean by lock? It doesn't sound like the standard definition of the term. Besides, using .lock just changes the file extension, not any exclusive rights to the file.

Are you trying to get exclusive access to the file? If so, then your Open statement should look something like:

Open "filename.ext" For Binary Access Read Lock Read Write As #1

Use whatever File Mode and Access you want, but the important part is the Lock modifier.

RageInTheMachine9532

Re: Locking files in VB6

steff kamush20-Jan-04 21:31

20-Jan-04 21:31

hi RageInTheMachine9532,

you r right i dint mean the std locking of files. i want many app instances to share a folder of .tif files. if app1 is using a file, it renames it with a .lock ext so app2 knows it is being modified by checking the ext.

before an app exits, it renames files its been using from .lock to .tif.

problem is if app1 crashes, the files remain with a .lock ext n neither app1 nor app2 can use them!

how do i handle this? i mean without resorting to the normal windows locking..

Rose | [Rose]

Re: Locking files in VB6

Dave Kreskowiak21-Jan-04 6:40

21-Jan-04 6:40

Well, the locking is the only "sure" way to control file access and you don't have to deal with renaming stuff back when you crash.

The problem you have is this:
When AppInstance1 checks for the availability of File1.tif, it's there. The next step, is for it to rename File1.tif to File1.locked. But, What if AppInstance2 found that File1.tif was available at (nearly) the same time, say, between AppInstance1 finding the file and renaming it? In this case, BOTH instances will find the file, but only one will succeed in renaming it. How is this case handled?

It's too much of a pain to write your own file locking scheme when Windows has locking built in. It also has the advantage of being "thread safe", where your custom scheme does not.

RageInTheMachine9532

still chart

Adhizzz19-Jan-04 21:20

Adhizzz

19-Jan-04 21:20

hi..i have still problem with chart,the problem how too generate graph from database,example access

adhizz

Re: still chart

steff kamush20-Jan-04 6:55

20-Jan-04 6:55

hi Adhizzz. i hope this helps

Print a Microsoft Access report from VB 6.0

As you may know, Microsoft Access provides a much more robust reporting
system than Visual Basic. As a result, if you use Access as a back-end
to your application, you may want to print Access reports from your VB
application. Fortunately, you can do just that with Automation.

The following code shows one way to do so, using late binding. remember to replace dbName and rptName with correct values:

Dim objAccess As Object

Private Sub Command1_Click()
Dim dbName As String
Dim rptName As String
Dim Preview As Long
Const acNormal = 0
Const acPreview = 2

dbName = "D:\PathToDB\db1.mdb"
rptName = "MyReportName"
Preview = acPreview 'acNormal

With objAccess
.OpenCurrentDatabase filepath:=dbName
If Preview = acPreview Then
.Visible = True
.DoCmd.OpenReport rptName, Preview
Else
.DoCmd.OpenReport rptName
End If
End With
End Sub

Private Sub Form_Load()
Set objAccess = CreateObject("Access.Application")
End Sub

Private Sub Form_Unload(Cancel As Integer)
On Error Resume Next
objAccess.Quit
On Error GoTo 0
Set objAccess = Nothing
End Sub

Re: still chart

steff kamush20-Jan-04 6:56