Field not validated from ABAP dictionary

HI ,

I have created ALV using OOP. . I implemented  F4 functionality on the field AUFNR on output . for validation on AUFNR i passed ref field(aufnr) and ref tab(aufk) in field catalog but still it is not validating .

field catalog :

i_fieldcat_line-fieldname   = c_aufnr.

  i_fieldcat_line-coltext     = c_prod.

  i_fieldcat_line-scrtext_m   = c_prod.

  i_fieldcat_line-col_opt     = c_x.

  i_fieldcat_line-edit        = c_x.

  i_fieldcat_line-f4availabl  = c_x.

  i_fieldcat_line-ref_table   = 'AUFK'.

  i_fieldcat_line-ref_field   = 'AUFNR'.

*  i_fieldcat_line-checktable  = c_aufk.

  i_fieldcat_line-key         = c_x.

  i_fieldcat_line-col_pos     = 2.

  i_fieldcat_line-outputlen   = 12.

could you please help me ?

Thanks ,

Mayank