The combination of data value, timestamp and quality (abbreviated sometimes as VTQ) is common in OPC. This combination is returned e.g. when an OPC item is read. Note that according to OPC specifications, the actual data value is only valid when the quality is Good or Uncertain (with a certain exception).

QuickOPC has a DAVtq object for this combination. The object provides access to individual elements of the VTQ combination, and also allows common operations such as comparisons. It can also be easily converted to a string containing textual representation of all its elements.

If you only want a textual representation for a data value from the VTQ, use the DisplayValue method. This is recommended over trying to extract the Value property and converting it to string, as you will automatically receive an empty string if the value is not valid according to OPC rules (e.g. Bad quality), and a null reference case is handled as well.