wpQueryRefreshFlags - Remarks

The refresh flags consist of a DIRTYBIT and a FOUNDBIT that are used to detect deleted files and new files when refreshing the contents of a folder.

For example, if you develop a subclass of wpFolder which contains objects that represent entries in a database (where the database may get updated independently from your objects), you might want to resynchronize your folder full of objects with the contents of the database. One possible technique follows:

• Loop through all of the objects in the folder and turn on the DIRTYBIT and turn off the FOUNDBIT for all of your objects.
  
• Loop through the database. For every entry in the database, find the corresponding object.
  
  a.
  If the object exists, turn on the FOUNDBIT for the object.
  b.
  If the object doesn't exist, create a new object with the FOUNDBIT turned on and the DIRTYBIT turned off.
  3.
  Loop through the objects in the folder again. For any object that has the FOUNDBIT turned off, delete the object (since there is no longer a corresponding entry in the database). For any object that has the DIRTYBIT turned on, update the view with the current contents of the object and turn its DIRTYBIT off.

  This kind of technique can be implemented using private flags, or by using the flags provided by the wpQueryRefreshFlags and wpSetRefreshFlags methods.

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