Advanced PowerBuilder

External User Objects

In this section, we explain you the theory behind the external user objects. With version 5.0, no example DLL are being shipped.

External user objects are created from underlying Windows DLLs. Lot of third party companies market windows controls with   lot of functionality ( typically they program in C/C++ ). You can use those objects ( available in DLL ) in PowerBuilder, by defining it as an external user object. For example, in PowerBuilder there is no control to display the progress of a process. The CPALETTE.DLL ( in version 4.0 ) in the EXAMPLES directory has a control which allows you to solve the problem.

It ultimately means that, these type of user objects let you use third party controls. When using controls derived from DLLs, you should be able to find out the events declared, how they respond and the limitations of the control in general. The events declared for the control are not displayed in the user object Painter, so you will have to go through the documentation provided with the DLL provider.

In the user object painter, you can still declare user events, functions, structures and variables, thus allowing you to access the control written in another language and to extend the functionality of the user object, even if you aren't familiar with that language.

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