The Userexits

Userexits our program routines to be called at -> triggers. that are standard userexits and application-specific userexits.


Standard Userexits

DataView provides a number of standard userexits. If efficiently used, they will cover the biggest part of the required functions in your application. Standard userexits are combined in a standard userexit library and classified according to their ability to be called at certain triggers. Usually you will only install -> standard menu userexits at On_Select- and On_Event triggers, -> standard mask userexits only at mask triggers and -> standard field userexits only at field triggers. Additionally you can call the -> universally usable standards userexits at all triggers. When you enter userexits into trigger fields of the DataView system masks, choice boxes in the -> System section will offer all standard userexits which can be called at the corresponding trigger.


Application-Specific Userexits

If the standard userexits are not sufficient, you create your own userexits to execute special functions in the application. When you design your own userexits, you should use the standard userexits as sub-routines as often as possible, in order to produce efficient and secure code. Detailed information about how to integrate your own userexits into the DataView application environment can be found in the -> Programing Interface, section Integrating Userexits. When you enter userexits into the trigger fields of the DataView system masks, choice boxes will automatically offer your application-specific userexits in the -> Application section.


Passing Parameters to Userexits

Whenever userexits are called at triggers you can pass them an application parameter. This syntax is:

Userexit name [parameter string]

For userexit calls at the On_Select and On_Event triggers you must pass the parameter string separated from the userexit name in an extra parameter field. The parameter string may not be longer than 255 characters. For calls at mask- and field triggers, you must add the parameter string to the userexit name in the trigger field, separated by spaces. There is no separate parameter field. The total entry may not be longer than 255 characters.

Some standard userexits demand application parameters. The standard menu userexit iwf_lis_ent to call lists, for instance, expects entity name and list name in the parameter string. If parameters are missing or if parameters are wrong, DataView will react with a standard behavior. For iwf_lis_ent for example a selection menu containing all existing entities in the data model will be automatically displayed if the entity name is missing. If the list name is missing, DataView will automatically create the default lists that belong to the entity. If the list name is wrong or no default list exists, DataView will output a corresponding message.

For your own application-specific userexits you can choose any structure for the parameter string. However, you must make sure that is correctly interpreted.