topic Re: screens in Application Development and Automation Discussions

screens

Former Member — Thu, 16 Nov 2006 12:17:16 GMT

what are the functions of events Start-of-selection.and at selection-screen?

Re: screens

seshatalpasai_madala — Thu, 16 Nov 2006 12:20:57 GMT

Hi,

AT selection screen is your PAI of the screen, here check your selection screen fields if the values entered or correct and in the right format etc. If you raise any error message the screen is shown again so that you can correct the error.

Start-of-selection is processed once you are sure that input is fine and you can read the data from the database using the input you have got.

So basically Start-of-selection is your business logic, AT selection-screen is an event to make sure the input given by the user is what you wanted or not.

Regards,

Sesh

Re: screens

Former Member — Thu, 16 Nov 2006 12:26:22 GMT

in which event user input validation will be done how it is?

Re: screens

seshatalpasai_madala — Thu, 16 Nov 2006 12:31:25 GMT

Hi,

INput validation is done in ATSELECTION-SCREEN event, you can also check for each field like this

PARAMETERS: para1 type string.

AT SELECTION SCREEN ON para1.

Check the value entered here

if you raise an type 'E' message here

the field para1 is the only field on the screen

open for input.

you can have as many as AT SELECTION-SCREEN ON events as you want

Alternatively you can have one AT SELECTION-SCREEN and check all the fields, but on type 'E' all the fields are open for input.

Regards,

Sesh

Re: screens

Former Member — Thu, 16 Nov 2006 13:32:31 GMT

Hi,

at slection-screen is used to validate the selection screen fields,

start-of-selection is used for selecting the data from database mainly.

Regards

Vijay

Re: screens

Former Member — Thu, 16 Nov 2006 16:51:59 GMT

Madhav,

At selection-screen : when there is some user id parameter is there in selection screen.

and you want to check the user id is exists in that system,

u validate user id in at selection screen.

start-of-selection: once u enter f8 what we need to do is mainly in start-of-selection.

-Anu.

Re: screens

Former Member — Thu, 16 Nov 2006 16:58:02 GMT

Hi,

Any Screen has four events...

1. Process before output - Which occurs before the page is displayed.

2. Process after input - Which occurs after the user has performed an action on the screen.

3. Process on value request - which is triggerd when a user requests for value help in a screen

4. Process on help request - This event is triggered when a user requests information on the elemetns in a screen.

As mentioned above, A Selection-screen also has the same events.

The PAI event of Selection-Screen is AT SELECTION-SCREEN. When the user interacts with the selection screen this event is triggered. Usually validations are performed in this event. You can also use this event to change the selection-screen elements if required.

Now before knowing about START-OF-SELECTION ..event..

You should know about events in program execution.

When a user executes a program the following events occur.

1. Load of Program - The program to be executed is loaded.

2. Initialization. - Any validations or settings required before the execution of the program are performed in this event.

If there is a selection-screen, then selection -screen events are performed.

Now the next operation would be to select data. To do this Start-of-Selection event is triggered. This event is triggered implicitly if not specified in the program. SAP performs data selection in START-OF-SELECTION. You can also fetch records in all other events. But this event is triggered implicitly by SAP, if not specified in the program.

I hope your questions are answered.

Regards,

Vara

Re: screens

Former Member — Thu, 16 Nov 2006 23:37:24 GMT

At-selection screen :

there are many options for this event .

1 ) This event is mainly used for validating any screen feilds Input data

2) Proviing Input help ( about the description of fireld and data input )

3) Providing F4 help possible entries

4) Modifying any screen fileds .

Start-of- selction .

1) Fetch data from data base tables

2) Process data

3) Automaticng locking on the database tables only in this table.

4) these get unlocks when end-of selection event occurs .

Regards