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Figure 17.4.
The hierarchy of file classes. |
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The Classes and Forms of the Subsystem |
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The forms in the subsystem include |
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The frmFileFactory form is not only a visual object for displaying information in files to your users, it is also helpful in debugging your classes in this subsystem to make sure the information is being saved (persisted) to the file in the format you desire. The frmTransferProgress form displays the progress of the number of records copied from or to a file. This form is helpful when dealing with very large files. |
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The notable classes in this subsystem include |
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The IPersistence class is important as an organizer of any event triggering the persistence of information, whether in a database or regular file. This class is not owned by the subsystem but is the gateway for the flow of events with a given client. The IFileSubsystem class is the interface for the subsystem, making sure that the proper response to an incoming event or message is handled as expected. The TaskProgress controller class controls the frmTaskProgress form. |
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