7.31.1 DEFINE_COM Parameters

CLASS

DESC

HELP

NAME

OPTIONS

SCOPE

REFERENCE

CLASS is the type of the component, for example command button, check box, form etc.For fields, the class can be a simple field such as #SALARY or any of its visualizations such as #SALARY.VISUAL or #SALARY.MYPART.

*VARIANT allows the use of a variant variable. You can read or write values from a variant variable. It has no properties. At the moment a better alternative is to use a Variant Variable.

The Options parameter can have a keyword LIST_ENTRIES with value *COMPUTE or *MAX. For example:

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*MAX sets the limit of entries to the maximum allowed by the containing component. Independent of whether the fields in the list are RDMLX or not, if the list is in an RDML component, it will be limited to RDML list entries but if it is an RDMLX component, it will be an RDMLX list

NAME is the unique name of this instance of a component.

The SCOPE parameter can be used to create component instances that are shared between different instances of owner components by specifying *SHARED as the value. When *SHARED is specified in the DEFINE_COM, only one single shared instance of a member component is created regardless of how many instances of the owner component are created.

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*APPLICATION variables are released when the application terminates. Care must be taken to ensure that the component classes used by an instance of a component at *APPLICATION scope are fully understood. All the component DLL's required to implement these component classes will remain in memory for the lifetime of the component instance and this could correspond to the lifetime of the application.

The REFERENCE parameter is used to define how the reference to the component being defined is resolved. The reference is created to the object defined by the CLASS parameter and assigned to the variable defined by the NAME parameter in the DEFINE_COM statement.

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RDMLX Functions can use the DEFINE_COM command. For functions that are running as *HEAVYUSAGE, the state of referenced components is retained between invocations. If the state is not to be retained, use components that are *DYNAMIC.

Use the DESC parameter to write a brief description for this instance of the component. It can be 40 characters long.

The setting of the OPTIONS parameter in the DEFINE_EVT command automatically set the value of the OPTIONS parameters for the EVTROUTINE command handling the event.

Use the HELP parameter to write a longer description for this instance of the component. The help text can be viewed using the Features option of the Help menu. It can be 250 characters long.