Hi,
Create a context attribute "VISIBILITY" of type WDY_BOOLEAN.
Bind this attribute to input field's property "ENABLED" in the view.
Initialise this variable in WDDOINIT of controller using below code :
Data: lo_context type ref to if_wd_context_element,
lv_enable type wd_this->element_context-field_enable.
lo_context = wd_context->get_element( ).
lv_enable = abap_true.
lo_context->set_attribute(name = 'FIELD_ENABLE' value = lv_enable).
Now select the action of which the field should be disabled and write same code just change the value of LV_ENABLE = abap_false.
Thanks
Deepak