Hi @lhartu and welcome to the CVB Forum,
If you use a GenICam compliant camera you need to access most of the features by using the NodeMap.
I found an example in this post:
https://forum.commonvisionblox.com/t/genapi-stringnode-value-access/263/2?u=sebastian
In your case it would probably be an integer node so you need to use the IntegerNode class:
auto integerNode = deviceNodeMap->Node<Cvb::IntegerNode>(CVB_LIT(DeviceVendorName));
auto value = integerNode->Value();