Byte array to Variant

Question

I have a byte array that contains for example

byte mac[6] = {0x00, 0x8a, 0x0C, 0x98, 0x11, 0x15}.

When inserting it to a database using this statement

m_pWiFiRecords->Fields->Item[varColumnIndex]->Value = _variant_t((char*)(pRecord->bss_id));

It saves it as an empty array because the first element = 0x00 and when casting it as a byte array it saves it as -1.

Could you help me in figuring out the problem?

edtheprogrammerguy · Accepted Answer · 2013-07-13 16:47:48Z

8

Here is what you would do to get the binary data into the _variant_t. If the database is set up to handle the binary data, it should work for you.

Note that the _variant_t will take care of doing a deep destroy on the SAFEARRAY when it goes out of scope, so you don't have to worry about doing a SafeArrayDestroy.

_variant_t var;
var.vt = VT_ARRAY | VT_UI1;

SAFEARRAYBOUND rgsabound[1];
rgsabound[0].cElements = 6;
rgsabound[0].lLbound = 0;

var.parray = SafeArrayCreate(VT_UI1,1,rgsabound);

void * pArrayData = NULL;    
SafeArrayAccessData(var.parray,&pArrayData);
memcpy(pArrayData, mac, 6); 
SafeArrayUnaccessData(var.parray);

m_pWiFiRecords->Fields->Item[varColumnIndex]->Value = var;

answered Jul 13, 2013 at 16:47

edtheprogrammerguy

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