Design-Level Considerations

Use the DESTROY statement

The .NET garbage collection service does not trigger the Destructor event for PowerBuilder objects. If you need to trigger the Destructor event for a nonvisual object, you must explicitly call the PowerScript DESTROY statement for that object.

Use multiple text patterns for string matching

If you want to test whether a string’s value contains any of a multiple set of matching text patterns, you can use the pipe character ( | ) in your .NET applications or components. The pipe character is a metacharacter in the .NET environment that functions as an OR operator, although it is not a metacharacter in the standard PowerBuilder client-server environment.

Therefore, when you call the Match function in the .NET environment, you can use pipe characters to determine if either of two (or one of many) text patterns match a string you are evaluating. In standard client-server applications, you can use the Match function to evaluate only one text pattern at a time.

Work around unsupported features

• Restrict impact of unsupported events — since unsupported events are never triggered, do not allow the logic in unsupported events to affect the logic flow of other events or functions.

  For example, if the code in an unsupported event changes the value of an instance variable, it can affect the logic flow in a supported event that uses that variable. Remove this type of coding from unsupported events.

• Avoid name conflicts — PowerBuilder allows two objects to have the same name if they are of different types. For example, you can use the name s_address to define a structure and a static text control or a nonvisual object in the same PowerBuilder application. The .NET environment does not allow two classes to have the same name. To enable your application to compile in .NET, you must not give the same name to multiple objects, even if they are of different types.
• Use global structures in inherited objects — using local structures in inherited objects can prevent deployment of a .NET project. To deploy the project, replace all local structures defined in inherited objects with global structures.

Avoid hindrances to application performance

Some functions and features that are fully supported can hinder application performance. Use these functions and features sparingly and avoid them where possible.

• Response windows and message boxes — use only when absolutely necessary. Response windows and message boxes require more server-side resources than other kinds of windows.
• Yield — avoid whenever possible, because it requires additional server-side resources.
• Timers — use sparingly and avoid including them on forms that require data entry. Timers periodically generate postbacks and can impede data entry. When you use them, delay the postbacks by appropriate scripting of client-side events.
• PFC — the DataWindow service in PFC handles many DataWindow events. Each event causes a postback for each mouse-click, which adversely affects application performance. Delay postbacks by scripting client-side events or cache DataWindow data in the client browser by setting the paging method property for the DataWindow object to XMLClient!.