An SAP Consultant

1. Lets say we have two drop down boxes. For every selected entry from first drop down box, if you want to set different kind of values, Supply function can be useful. 
2. Lets say we have two tables. For every selected row from first Table, if you have multiple elements to be shown in table, Supply function can be useful. 

• Create Web Dynpro component and Save. 

• Go to Component Controller context ->Create one root node(EMP_INFO) under context node as shown below for Employee information table. Set cardinality to 0..n

•  Create one child node e.g IT0006_DATA under EMP_INFO root node where EMP_INFO is the source of supply for the node IT0006_DATA. Cardinality 0...n and Supply function GET_ADD_DATA should be mentioned. 

• Go to view VIEW1 ->Context. Map component controller context to view context by drag and drop method. 

•  Go to view layout ->Set ROOTUIELEMENTCONTAINER layout to MatrixLayout type.
• Create EMP_INFO table UI Element ->Set table caption and Table Layout data property to MatrixHeadData. Create binding as shown in the print screen.  

•   Create IT0006_DATA table UI Element ->Set table caption and Table Layout data property to MatrixHeadData. Create binding as shown in the print screen.

•  Save and Go to COMPONENTCONTROLLER - >Methods - >WDDOINIT. Write the below code 

METHOD wddoinit.
  DATA lo_nd_emp_info TYPE REF TO if_wd_context_node.

  DATA lt_emp_info TYPE wd_this->elements_emp_info.

* navigate from  to  via lead selection
  lo_nd_emp_info = wd_context->get_child_node( name = wd_this->wdctx_emp_info ).
  SELECT *
    FROM pa0002
    INTO CORRESPONDING FIELDS OF TABLE lt_emp_info
    UP TO 50 ROWS.

  lo_nd_emp_info->bind_table( new_items = lt_emp_info set_initial_elements = abap_true ).

ENDMETHOD.

•   COMPONENTCONTROLLER - >Methods - >WDDOINIT. Write the below code 

METHOD get_add_data .
* General Notes
* =============
* A common scenario for a supply method is to aquire key
* informations from the parameter  and then
* to invoke a data provider.
* A free navigation thru the context, especially to nodes on
* the same or deeper hierachical level is strongly discouraged,
* because such a strategy may easily lead to unresolvable
* situations!!

*  if necessary, get static attributes of parent element
  DATA ls_parent_attributes TYPE wd_this->element_emp_info.
  parent_element->get_static_attributes(
    IMPORTING
      static_attributes = ls_parent_attributes ).

  DATA lo_nd_it0006_data TYPE REF TO if_wd_context_node.

  DATA lt_it0006_data TYPE wd_this->elements_it0006_data.

* navigate from  to  via lead selection
  lo_nd_it0006_data = wd_context->path_get_node( path = `EMP_INFO.IT0006_DATA` ).
  SELECT *
    FROM pa0006
    INTO CORRESPONDING FIELDS OF TABLE lt_it0006_data
    WHERE pernr EQ ls_parent_attributes-pernr.
  lo_nd_it0006_data->bind_table( new_items = lt_it0006_data set_initial_elements = abap_true ).

ENDMETHOD.

•  Activate the Web Dynpro Component
• Create Web Dynpro application 

• Execute the Web Dynpro application.