Following generic types are available for use with OPC Data Access and OPC XML-DA:

• DAVtq<T>: Holds typed data value (of type T), timestamp, and quality.
• DAVtqResult<T>: Holds result of an operation in form of a typed DAVtq<T> (value, timestamp, quality).
• DAItemValueArguments<T>: Arguments for an operation on an OPC item. Carries a value of type T.
• DAItemVtqArguments<T>: Arguments for an operation on an OPC item. Carries a DAVtq<T> object.
• EasyDAItemSubscriptionArguments<T>:  Arguments for subscribing to an OPC item of type T.
• EasyDAItemChangedEventArgs<T>: Data of an event or callback for a significant change in OPC item of type T.

These types are used with generic access extensions for OPC items (see Generic Access) and with generic access extensions for OPC properties (see Generic Access). They are also use with the Live Mapping Model.

For example, you can call the EasyDAClient.ReadItem<T> extension method with a given type T, and receive back a DAVtq<T> object with a TypedValue already properly typed as T.

Noted that if the untyped property on the base (non-generic) type has a name like XXXX, the corresponding typed property on the generic type has a name like TypedXXXX. For example, for an untyped property DAVtqResult.Vtq, there is a corresponding typed property DAVtqResult<T>.TypedVtq.