download a file

hi i i've the following problem, i need download i fiel into web dynpro application i'm using file download action but thios action request me a node with suply file and a component of type xstring but when i invoke the follow code i can't insert the context from a internal an d i need download the context of the table from webdynpro

data conv_out type ref to cl_abap_conv_out_ce.

data struct type if_main=>element_file_suply.

• fill the file content

conv_out = cl_abap_conv_out_ce=>create( encoding = 'UTF-8' ).

conv_out->convert(

exporting

data = here data

importing

buffer = struct-file ).

node->bind_structure( struct ).

so i need download a table with all the column inside anyone know how i can do it