I am trying to pass a 2d array called DataArray into an ATL COM component
from my C++ Managed Class Library.

 int ChannelArray __gc[] = new int __gc[lNumChans];
 short DataArray __gc[,] = new short __gc[lNumChans, lNumPoints];

 int k,j;
 for (k=0; k<lNumChans; k++)
 {
  ChannelArray[k] = k+1;
 }

 pTHDC->ReadData(&ChannelArray,lStartPoint, lNumPoints, &DataArray);

The ATL COM component method looks like this

HRESULT ReadData([in] SAFEARRAY (long) *psaChannelArray, [in] long
lStartPoint, [in] long lNumPoints, [in, out] SAFEARRAY (short)
*psaDataArray);

When I try to compile I get the error

c:\1\DAQ_Test_VC_NET\DAQ_Test\DAQ_Test.cpp(64): error C2664:
'QXTHDCLib::THDITClass::ReadData' : cannot convert parameter 4 from 'short
(*) __gc[,]' to 'short (__gc *) __gc[]'

What do I need to change ??

Cheers

I suggest you have a look at the following articles:

Troubleshooting .NET Interoperability
http://msdn.microsoft.com/library/en-us/dv_vstechart/html/vbtchTroubl...
ngNETInteroperability.asp

The section "Multidimensional C-Style Arrays" describes this topic in
detailed. Basically, you should use the ILDASM.exe tool to change the IL
code from:

method public hidebysig newslot virtual
instance void  TwoDimArray([in] int32 cDim,
[in] native int aMatrix) runtime managed internalcall

to:

method public hidebysig newslot virtual
instance void  TwoDimArray([in] int32 cDim,
[in] int32[,] marshal([+0]) aMatrix) runtime managed internalcall

You may refer the article to get more detailed information.

I hope this is helpful.

Best regards,

Lion Shi, MCSE, MCSD
Microsoft Support Engineer

This posting is provided "AS IS" with no warranties, and confers no rights.
You assume all risk for your use.  2001 Microsoft Corporation. All rights
reserved.
--------------------

    Subject: Passing a 2d array from .NET to COM
    Date: Tue, 23 Jul 2002 10:27:44 +0100
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    Hi,

    I am trying to pass a 2d array called DataArray into an ATL COM
component
    from my C++ Managed Class Library.

     int ChannelArray __gc[] = new int __gc[lNumChans];
     short DataArray __gc[,] = new short __gc[lNumChans, lNumPoints];

     int k,j;
     for (k=0; k<lNumChans; k++)
     {
      ChannelArray[k] = k+1;
     }

     pTHDC->ReadData(&ChannelArray,lStartPoint, lNumPoints, &DataArray);

    The ATL COM component method looks like this

    HRESULT ReadData([in] SAFEARRAY (long) *psaChannelArray, [in] long
    lStartPoint, [in] long lNumPoints, [in, out] SAFEARRAY (short)
    *psaDataArray);

    When I try to compile I get the error

    c:\1\DAQ_Test_VC_NET\DAQ_Test\DAQ_Test.cpp(64): error C2664:
    'QXTHDCLib::THDITClass::ReadData' : cannot convert parameter 4 from
'short
    (*) __gc[,]' to 'short (__gc *) __gc[]'

    What do I need to change ??

    Cheers