what is the purpose of this (?=) ?

[Former Member]

hi friends...

I am practising the WDA programs...

in that they hav used this code

data wd_table type ref to cl_wd_table.

wd_table ?= view->get_element( 'TABLE' ).

wd_this->table_control ?= wd_table->_method_handler.

wd_this->table_control->set_key_attribute_name( 'MATNR' ).

i don't know why they used this code...

here ( ?= ) what is the purpose of this ?= ?

what is the purpose of this class cl_wd_table ?

i am not clear with all statement, can you guide me..

i am waiting for ur reply

regards

Deva

[Former Member]

cl_wd_table is runtime class for Table UI Element.

Look out for Table Details in : http://help.sap.com/saphelp_nw70/helpdata/EN/b5/ac884118aa1709e10000000a155106/frameset.htm

Thanx.

[Former Member]

solved

[former_member40425]

Hi,

This question belongs to ABAP general.

Check out the following thread.

Regards,

Rohit

[Former Member]

Hi ,

The symbol ?= symbol represents down cast that means we are assging the properties of the parent to the child class . You can observe here wht is the parent class and wht is the child and wht they are tryng to assgin here .

Then you will clearly understand why are they usign this symbol .

GoodDay.

Regards,

Sana.

[Former Member]

?= this is called downcast or narrow casting operator in abap.

The purpose of this is assignment between reference variables in which the static type of the target varible more specific than the static type of the source varible.

Check this link, hope it helps !

[https://help.sap.com/saphelp_nw70ehp1/helpdata/en/c3/225b5f54f411d194a60000e8353423/frameset.htm]

Radhika.