Hi Abhijit,
I am not sure how to create custom tree component in adobe form.
Just a suggestion, you can use label to show the different level of depth of your BOM.
Example.
1. XXX
1.1. XXXX
1.1.1 XXX
1.1.2 XXX
...
1.2.
1.2.1 XXX
2. XXX
Of course you can use different formatting to differentiate their level too, example your first level will be always in bold 1.XXX and you can add indention to it too.
The idea is to use nested table structure. But first thing you need to find out is, how depth you want to display the BOM item, as you need to define the table upfront and layout design upfront.
One good example I can rememebr of is HAP_PDF_OFFLINE_FORM SAP standard form, main table is T_COL_CELL, and it it displaying different elements(checkbox, dropdown, textfield) based on the type.
The idea is, replace those checkbox dropdown textfield as level 2 level 3 level 4 and etc, and give them different left margin for indention purposes.
You might want to understand how subform as table row works.
http://****************/Tutorials/AdobeForms/Table/page1.htm
Hope this helps.
regards,
Xiang Li