一、module
You can use MODULE as a keyword only at the events PBO and PAI. At the events
POH and
POV, you can use
MODULE only as an addition to the
FIELD statement.
只能在PBO和 PAI事件中使用module作为关键字，在POH和 POV中 module只能被用作field语句中的附加选项。
二、LOAD-Of-PROGRAM 和
INITIALIZATION
The event LOAD-Of-PROGRAM should mainly be used to initialize global data when calling external procedures or
Transactions. If you call executable programs with
SUBMIT, we recommend that you use the event
INITIALIZATION, as the
Starting values for parameter and selection criteria are set after
LOAD-OF-PROGRAM (see
program flow after SUBMIT).
load-of-program事件主要是在call一个external procedures 或者 transaction 的时候，用于初始化全局数据。
如果你是用submit去call一个可执行程序，我们建议你使用initialization事件为parameter赋值，而选择屏幕上的信息在load-of-program事件中进行设置。
在一个report中会首先执行LOAD-Of-PROGRAM ，然后才会执行INITIALIZATION事件。
比如下面的测试程序：
REPORT ztest08.
LOAD-OF-PROGRAM.
WRITE: /
'I am load-of-program'.
INITIALIZATION.
WRITE : /
'I ma initialization'.
最后的输出结果为：
I am load-of-program
I ma initialization
三、
The screen flow logic, as an ABAP program, is structured from processing blocks. Possible processing blocks are the four event blocks for the screen events
PBO,
PAI,
POH, and
POV, which all start with the key word
PROCESS. These event blocks contain a small set of statements that are described in the following sections, and which offer the
the following functions:
- Call dialog modules of the ABAP program using
MODULE
- Control data transports to the ABAP program and treat
error messages using FIELD and
CHAIN
- Execute loops using
table controls with LOOP
- Call
subscreens using CALL SUBSCREEN
（1）PBO、PAI、POH、POV这些屏幕事件，都是通过process关键字，来调用abap程序块来实现的。
（2）这些程序块包含了一系列包含下述功能的代码
- 调用dialog modules，这是通过module来实现的
- 控制数据传输到abap程序、处理错误信息，这是通过field和chain来实现的
- 执行表的循环，这是通过loop实现的
- 调用subscreen，这是通过call subscreen来实现的。