How to pass double[,] parameter to an interop dll method?

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I have created interop dll for labview VI's.
I am using interop dll in .NET environment.
The method signature is:

public static void ReconstructRawData(byte COMPort, double[] FlowValuesFullScaleFlow, double[] TemperaturesC, ErrorCluster errorin, byte Gastype, bool ValueFormatrealunitsFalse, out ushort GasDensity, out double[,] RawData, out ushort MaxFlow, out ushort GasID, out ErrorCluster errorout);

I am calling as shown below:

byte bComPort = byte.Parse("1");
byte bGasType = byte.Parse("6");
bool blnValueFromatFalse = false;
ushort GasDensity = 0;
double[,] RawData = new double[100, 100];
//double[][] RawData = null;
ushort MaxFlow = 0;
ushort GasID = 0;
ErrorCluster ErrorIn = new ErrorCluster();
double[] dblFlowValue = new double[2];
dblFlowValue[0] = 20;
dblFlowValue[1] = 50;
double[] dblTempValue = new double[2];
dblTempValue[0] = 10;
dblTempValue[2]= 20;

But I am getting memory error "Attempted to read or write protected memory. This is often an indication that other memory is corrupt"

Stack Trace:at System.Runtime.InteropServices.Marshal.ReadInt32(IntPtr ptr, Int32 ofs)
at System.Runtime.InteropServices.Marshal.ReadIntPtr(IntPtr ptr)
at NationalInstruments.LabVIEW.Interop.DataMarshal.MarshalArrayOut(Type arrayType, IntPtr data)
at NationalInstruments.LabVIEW.Interop.DataMarshal.MarshalOutputArray(IntPtr entryPointDataSpace, Type arrayType, Int32 terminalIndex)

Now how to send RawData(multidimentional array) to an method of interop dll?

Posted 2-Sep-10 2:31am

Member 2847006

Updated 2-Sep-10 2:37am

LittleYellowBird

v3

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Erich Ledesma · Accepted Answer · 2010-09-02T04:29:00

I've barely used labview and never used interop with it. So excuse me if I'm not a good help.

There are a couple of problems involved here.

1- By using out double[,] I'm guessing you want to get a memory block, reserved in the labview VI. This is a problem by it self. Memory blocks cannot be moved freely between managed and unmanaged code.
As you say you want to "send" a bi dimensional array to labview. You might want to try to leave no attribute (out nor ref) to the array parameter.

2- Parameters passed to "native" libraries are usually subjected to Marshalling, there is currently no implementation for a Marshalling a multi dimensional array, at least that I know of, I had to build my own some years ago.

I guess lab view should have definition for Custom Marshallers or you'll have to build your own:
http://msdn.microsoft.com/en-us/library/d3cxf9f0(v=VS.90).aspx[^]
link above has been fixed, the "x" at the very end was missing. Upss!!

Give me some Labview API references and I'll give it another look.

Good luck!!