Visual Basic

Dave Kreskowiak1-Dec-09 4:48

1-Dec-09 4:48

What does your VB.NET code look like?

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Sondre Minnesjord1-Dec-09 4:56

1-Dec-09 4:56

I knew I forgot something....

Here is the similar section of code in VB.net:

Public Sub NodeDispl()

Dim pdDisps(5) As Double
Dim ObjOpenSTAAD = CreateObject("OpenSTAAD.Output.1")
ObjOpenSTAAD.SelectSTAADFile("C:\temp\staadtest.std")

ObjOpenSTAAD.GetNodeDisplacements(7, 101, pdDisps(0))

ObjOpenSTAAD.CloseSTAADFile()

ObjOpenSTAAD = Nothing

End Sub

Dave Kreskowiak1-Dec-09 5:09

1-Dec-09 5:09

OK, since OpenSTAAS is a COM object, I suggest ditching the late binding you're using now and go for early binding instead. Open the project propties and click on the References tab. Add a COM reference for your library (it'll show up in the list somewhere) and in your code, rewrite to this:

Public Sub NodeDispl()
    Dim pdDisps(5) As Double
    Dim objOpenSTAAD As New OpenSTAAD.Output
    objOpenSTAAD.SelectSTAADFile("C:\temp\staadtext.std")
    objOpenSTAAD.GetNodeDisplacements(7, 101, pdDisps)
    objOpenSTAAD.CloseSTAASFile()
End Sub

The code may not as written, but it'll be close.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Sondre Minnesjord1-Dec-09 20:17

1-Dec-09 20:17

Thanks a lot! Now it all works like expected.

It was as I suspected; a trivial solution to the problem. However, I'm quite new to programming and wasn't even aware of the concept of early/late binding. However, in the example I copied (written in VBA), late binding was used. Just out of curiousity - is there a reason why this is used at all?

Dave Kreskowiak2-Dec-09 0:38

2-Dec-09 0:38

Yes. Sometimes you can use different versions of an object and you don't know which one(s) is/are installed. Since early binding is a bit "version" dependant, if the correct version isn't installed when you run the app, every though some version of the component is installed, your app will fail.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Sondre Minnesjord18-Feb-10 21:22

18-Feb-10 21:22

Hi,

I've run into a major problem. As described earlier, I couldn't figure out how to make my code work in vb.NET, when it worked fine in VBA. That problem was resolved and everything has worked fine until yesterday when suddenly everything stopped working. I think I've managed to isolate the problem, but cannot figure out why it occurs:

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _
Handles Button2.Click

Dim Analysis As New OPENSTAADLib.Output
Dim nLC As Integer = 0

Analysis.SelectSTAADFile("c:\temp\PSDesigner\PS-1_Operation.std")
Analysis.AnalyzeStructure("NORWAY")
Analysis.GetLoadCombinationCaseCount(nLC)
MsgBox(nLC)

End Sub

Short explanation:

OPENSTAADLib is an external COM component which I had to reference in order to access. The OPENSTAADLib.Output object is used to run an input file for a structural analysis. The "AnalyzeStructure" command is the actual analysis, whereas the GetLoadCombinationsCaseCount is an example of a function to retrieve information from the results of the analysis.

- Now I get this error message: "Attempted to read or write protected memory. This is often an indication that other memory is corrupt."
- I tried putting the functions inside Try blocks, and made them loop back a number of times in order to retry. That helped a little, but it seems to be all random whether it works or not.
- when I start the debugging, I can run the sub once or even twice without problems, but then it won't work any longer.

The exception message says: "External component has thrown an exception". I also have seen the System out of memory exception, even though (according to the windows task manager) the program does not use a lot of resources.

I am still a quite unexperienced programmer and I really don't know how to resolve this or even where to begin look for answers (except her on codeproject, of course).

Sondre M

Dave Kreskowiak19-Feb-10 1:42

19-Feb-10 1:42

I know nothing of your component, so I can only guess.

The first thing I'd check would be the validity of the PS-1_Operation.std file.

Next, I'd open Task Manager, turn on some addition columns, like Handles, Threads, User Objects, Memory Peak Working Set, Cand Commit Size. Then I'd watch the app run again, watching those numbers. You CAN run the machine "out of memory" by leaking things like Handles.

I'd also throw the app at a profilers, like ANTS.

It's possible that you're not freeing up or releasing this component properly.

A guide to posting questions on CodeProject[^]

Dave Kreskowiak
Microsoft MVP
Visual Developer - Visual Basic
2006, 2007, 2008
But no longer in 2009...

Sondre Minnesjord19-Feb-10 2:42

19-Feb-10 2:42

The file applied is definetely valid. The .std is really only a textfile which I have no problem running using the GUI of the analysis program (STAAD.Pro).

I will try and look more closely into the Task Manager although I'm not quite sure what to look for.

Earlier today I opened up a backup copy of the code from last month, hoping that it would still work, but even if it worked better than the latest version, eventually it too failed. The reason why it failed now and not earlier may be that the program haven't been tested for any long "sessions" - until now. This seems to be the problem.

My prime suspect was really something memory related, which would probably explain why the program failed afted a while (after several runs of the analysis). But then I started a blank VB project with the few lines of code as displayed in the previous post, and it failed at once.

How can I make sure that I free up or release the component?

Dave Kreskowiak19-Feb-10 12:52