How to detect checked status in a virtual TAdvTreeView

[FANBERG_Victor]

I have a virtual tree view that I want to uncheck the n-th checked box. So, I created a sample project just to uncheck the first one and the only option I can see working is something like maintaining an external vector of the checked status of each node. Is there any chance of something like the following working?

void __fastcall TForm1::btnClearFirstIconClick(TObject *Sender)
{
int NullsFound = 0;
TAdvTreeViewVirtualNode *ANode = AdvTreeView1->GetFirstRootVirtualNode();
TAdvTreeViewNode *aNode;

while (ANode) {
	aNode = ANode->Node;    // Always returns NULL
	if (aNode) {
		if (aNode->Checked[0]) {
			AdvTreeView1->BeginUpdate();
			aNode->Checked[0] = false;
			AdvTreeView1->EndUpdate();
			break;
		}
	} else {
		NullsFound ++;
	}

	ANode = AdvTreeView1->GetNextVirtualNode(ANode);
}

if (NullsFound) {
	ShowMessage(UnicodeString(NullsFound) + L" Nulls found");
}

}

If the above is executed in a tree with 9 nodes, the message displayed will be "9 Nulls found", so I know it is correctly traversing the tree.

[brunofierens]

The state of checkboxes is kept per node via:
Node.CheckStates[AColumn]: boolean;