visual studio - How to apply data validation for drop down in excel sheet by C# code -

i working on excel plugin , trying create dropdowns column can have column cells data.

for example:

column h's name type , has data "animal, human".
column i's name animal , has data "dog, cat, rat"
column j's name dog , has data "dog1, dog2, dog3"
column k's name cat , has data "cat1 , cat2 , cat3"
column l's name rat , has data "rat1 , rat2 , rat3"

1    h               j        k        l 2   type     name     dog      cat      rat 3   animal   dog      dog1     cat1     rat1 4   human    cat      dog2     cat2     rat2 5            rat      dog3     cat3     rat3 

i linked column column h formula:

firstrow.validation.add(excel.xldvtype.xlvalidatelist, excel.xldvalertstyle.xlvalidalertstop, excel.xlformatconditionoperator.xlbetween,                 "=" + activeworksheet.name + "!" + activeworksheet.get_range("type").addresslocal); 

same formula applied b2 changing range name.

now cell a1 has dropdown list of "animal, human".

cell b1's dropdown list dependent on cell a1.

so if user selecting a1 data "animal", dropdown list of b1 should according a1's dropdown data "dog, cat, rat, lion"

again if user selecting d1, should according selected data b1.

in excel selected cells , go data validation tab, select type list , applied formula like:

=indirect($a1) 

and working fine column b1.

how can apply c# code.?

please let me know if sentence not clear.