4GL Access: RW

The Marker attribute enables bitmap objects to be characterized and distinguished.

Unlike FileHandle (see FileHandle Attribute) and DBHandle (see DBHandle Attribute), setting the marker attribute does not trigger a change of bitmap. Consequently, duplicated bitmap objects can be distinguished from the originals by setting a different marker value. The following code illustrates how you could achieve this:

Retrieving large sets of records that include bitmap object dbhandles or filehandles into an array from the database automatically triggers correspondingly large numbers of further selects or retrievals from disk to populate these bitmap objects, many of which may never be displayed. You can use the Marker attribute to avoid this problem. Retrieving the handle instead into the Marker attribute avoids the triggered retrieval; the value can then be copied from the marker into the filehandle or dbhandle attribute at the appropriate moment. The following code illustrates how you might do this:

If the BitmapObject is attached to a FormField or a stored TaggedValue Item, using this in your program during development may change your frame's source definition. See BitmapObject Attributes and Methods Affecting the Frame Source (see BitmapObject Class).