Is it possible to convert LabView data into OLE variant?

[Daniel_Chile]

Hi. I'm using Activex Data Objects (ADO) to communicate with MySQL. Some ActiveX methods give OLE variant output, with "Variant Type" like "VT_ARRAY|VT_UI1", "VT_UI1" or "VT_BSTR". With some deduction and trial and error is relatively simple to extract data from this OLE variants and convert them to LabView data types. The problem is when I try to input variant data to some ActiveX methods, it almost always give me errors, I suppose because it expects the same type of the outputs, this is: OLE variants. Now, the question is: ¿Is there any way to convert LabView data into OLE variant data? ¿How?

I've been searching and found a lot of posts about problems when passing variant data into ActiveX, saying that sometimes SAFEARRAYs are needed, sometimes saying that there were some bugs in LV6, giving some workarounds to this bug and saying that it is fixed in LV7.1, but the supposed workarounds don't work and the bug is still present in LV7.1, if it is really a bug.

I think that if I could put LV data into OLE variant shape I may find an answer and solution to this matter.

Thank you

Daniel R.
UdeC - Chile

[Lycangeek]

Below I describe how to handle OLE Variants, but I wanted to mention that LabVIEW does have a Database Connectivity toolkit (http://sine.ni.com/nips/cds/view/p/lang/en/nid/6429) that has already created a set of VIs for ADO. You might check that out first.

However, handling OLE Variants in LabVIEW is automatic. LabVIEW itself has a variant datatype. When you use the ActiveX property or invoke nodes and one of the parameters is an OLE Variant, it is automatically converted to a LV Variant. You can then use the LV Variant VIs (such as "Variant to Data" and "To Variant").