.NET Refnum pointing to a labview array for an input to a .NET Invoke Method HOW DO I

[Tim_C.]

Can anyone show me how to make a valid .NET Refnum to a Labview array that I can use an an input to a .NET Invoke Method that require a .NET Rufnum input that refences an array?

Thanks in advance

Tim C.

[HJPhilippi]

The .NET invoke node needs an array of what?

If it's e.g. a simple string array, the ordinary LV string array type will match. If on the other hand it's an array of a .NET defined type, you need to create the "nested" type with a .NET constructor node and build an array from it accordingly.

Understood?

Greetings,

Hans

[Tim_C.]

Hello

It turns out that the .NET DLL is expecting a pointer to an array.  I went in and looked at the code and the function is using the ByRef function to setup the field variable.  There are two ByRef variables.  Database and Field.  Database is expecting a string path to the database file

and a second string that designates the seperator.  The Field Variable appears to want a pointer to an array but I canoont get this to work.

I have looked at all the constructor and methods but no combination seems to work.  I keep getting a .NET exception error.

Thanks

Tim C.

[HJPhilippi]

The ByRef parameter option indicates that the called function may want to write data back into the specified parameters themselves.
Anyway, I still need some more information to help you further. Could you paste the code or at least the signature of the VB.NET function you're calling?

Greetings,
Hans

[Tim_C.]

Here is the funtion

    Public Function SimpleMovingAverage(ByRef Data As Database, ByRef Source As Field, ByVal Periods As Integer, Optional ByVal FieldAliasName As String = "") As RecordSet

        Dim Avg As Double
        Dim Period As Short
        Dim Record As Short
        Dim RecordCount As Short
        Dim Start As Short
        Dim Field1 As New Field()
        Dim Results As New RecordSet()

        On Error GoTo UnexpectedError

        If FieldAliasName = "" Then FieldAliasName = "SimpleMovingAverage"

        RecordCount = Data.getRecordCount

        Field1.initialize(RecordCount, FieldAliasName)

        Start = Periods + 1
        Data.setPosition(Start)

        'Loop through each record in Recordset
        For Record = Start To RecordCount

            Avg = 0

            'Loop backwards through each period
            For Period = 1 To Periods
                Avg = Avg + Source.getValue(Data.getPosition)
                Data.MovePrevious()
            Next Period

            'Jump forward to last position
            Data.setPosition(Data.getPosition + Periods)

            'Calculate moving average
            Avg = Avg / Periods
            Field1.setValue(Data.getPosition, Avg)

            Data.MoveNext()

            System.Windows.Forms.Application.DoEvents()

        Next Record

        Data.MoveFirst()
        Results.addField(Field1)
        SimpleMovingAverage = Results

        Exit Function
UnexpectedError:
        Err.Raise(1105, "MovingAverage.SimpleMovingAverage.UnexpectedError", "An unexpected error has occured")
        Exit Function

    End Function

[HJPhilippi]

...ahem, actually I don't see any array parameters in the code signature. But you were asking for handing over arrays?!?

Looks like some old VB ADO code has been transferred to VB.NET. The Database and Field parameters are not arrays but ADO classes or types defined somewhere else in your code, as far as I can see. They may be derived from other collection or array based classes, but I'd bet they're not.
The function you've posted simply does an evaluation of the data within a Database object using the Field object, both handed over as parameters, so their actual values must originate somewhere else in your calling LabVIEW code...

Sorry, but this takes some more investigation of the whole project to help you further.

Greetings,
Hans

[Lycangeek]

I'm also not sure what version of LabVIEW you're running, but we did change the mapping some in 8.2 so that byref parameters of primatives (int, string, arrays) showed up correctly (i.e., you don't need to make them .NET references first).

However, if you ever do need to convert a LV primative into a .NET refnum, use To .NET Refnum.vi in <vi.lib>/platform/dotnet.llb