External data provides a way for the Creo Parametric application to store its own private information about a Creo Parametric model within the model file. The data is built and interrogated by the application as a workspace data structure. It is saved to the model file when the model is saved, and retrieved when the model is retrieved. The external data is otherwise ignored by Creo Parametric; the application has complete control over form and content.

The external data for a specific Creo Parametric model is broken down into classes and slots. A class is a named ‘‘bin’’ for your data, and identifies it as yours so no other Creo Parametric API application (or other classes in your own application) will use it by mistake. An application usually needs only one class. The class name should be unique for each application and describe the role of the data in your application.

Each class contains a set of data slots. Each slot is identified by an identifier and optionally, a name. A slot contains a single data item of one of the following types:

The Web.Link interfaces used to access external data in Creo Parametric are:

Web.Link and Creo TOOLKIT share external data in the same manner. Web.Link external data is accessible by Creo TOOLKIT and the reverse is also true. However, an error will result if Web.Link attempts to access external data previously stored by Creo TOOLKIT as a stream.

Methods Introduced:

The method pfcModel.AccessExternalData() prepares Creo Parametric to read external data from the model file. It returns the pfcExternalDataAccess object that is used to read and write data. This method should be called only once for any given model in session.

The method pfcModel.TerminateExternalData() stops Creo Parametric from accessing external data in a model. When you use this method all external data in the model will be removed. Permanent removal will occur when the model is saved.

The method pfcExternalDataAccess.IsValid() determines if the pfcExternalDataAccess object can be used to read and write data.

Methods and Properties Introduced:

The first step in storing external data in a new class and slot is to set up a class using the method pfcExternalDataAccess.CreateClass(), which provides the class name. The method outputs pfcExternalDataClass, used by the application to reference the class.

The next step is to use pfcExternalDataClass.CreateSlot() to create an empty data slot and input a slot name. The method outputs a pfcExternalDataSlot object to identify the new slot.

The property pfcExternalDataSlot.Value specifies the data type of a slot and writes an item of that type to the slot. The input is a pfcExternalData object that you can create by calling any one of the methods in the next section.

Methods Introduced:

These methods initialize a pfcExternalData object with the appropriate data inputs.

Methods and Properties Introduced:

For improved performance, external data is not loaded automatically into memory with the model. When the model is in session, call the method pfcExternalDataAccess.LoadAll() to retrieve all the external data for the specified model from the Creo Parametric model file and put it in the workspace. The method needs to be called only once to retrieve all the data.

The method pfcExternalDataAccess.ListClasses() returns a sequence of pfcExternalDataClasses registered in the model. The method pfcExternalDataClass.ListSlots() provide a sequence of pfcExternalDataSlots existing for each class.

To find out a data type of a pfcExternalData, call pfcExternalData.discr and then call one of these properties to get the data, depending on the data type: