Re: [VBA] Need help with MDL Wrapper Function for mdlSheetDef_setBorderAttachmentId

Yongan.Fu:

ElementID is not a structure, it is just a base type __int64

Correct — but only for MDL and C++, which support the __int64 data type. Microsoft invented VBA before 64-bit processors existed and does not support the 64-bit integer data type, which is why Bentley Systems invented the DLong UDT. MDL's ElementID is an alias for __int64.

The problem is this …

 ElementID id = 0;
 mdlSheetDef_getBorderAttachmentId (..., &id);

In the above fragment, the variable that contains the element ID (a 64-bit number) is passed by address. C/C++ languages work can modify the contents of an address. It's the equivalent of VBA ByRef. However, because VBA can't cope with 64-bit integers, we have to use the DLong UDT. In this case the MDL wrapper declaration from MDL help is correct …

Declare Function mdlSheetDef_getBorderAttachmentId _
   Lib "stdmdlbltin.dll" ( _
   ByVal sheetDefIn As Long , _
   ByRef borderAttachmentIdOut As DLong ) As Long

The MDL wrapper for the setter function is incorrect, because it wants to pass a DLong by value …

Declare Function mdlSheetDef_setBorderAttachmentId _
 Lib "stdmdlbltin.dll" ( _
 ByVal sheetDefIn As Long , _
ByVal borderAttachmentIdIn As DLong ) As Long

We can edit that declaration so that VBA will parse it correctly …

Declare Function mdlSheetDef_setBorderAttachmentId _
 Lib "stdmdlbltin.dll" ( _
 ByVal sheetDefIn As Long , _
ByRef borderAttachmentIdIn As DLong ) As Long

However, changing that declaration does not change the underlying code. We don't know how that MDL wrapper is implemented. I suspect that there may be some internal confusion in the conversion from the internal __int64 and the VBA DLong passed by address.

Regards, Jon Summers
LA Solutions