displaying facname when i click the facid using asp.net C#

Question

 

Faculty table structure as follows
 

Facid       bigint
Facname varchar

 
Faculty table records as follows
 

Facid  Facname
 
1     G Sekar
2    R Kumar
3    S Janka
4   R Rajesh
5   V Gopi
 

Bthfac table structure as follows
 

Bthid     bigint
Bfid      bigint
Facid    varchar
 
Bthfac table records as follows
 

Bthid Bfid    Facid
 
1        1      1,3,5
2        2      2,4,5
3        3      3,4
4        4     1,2,5
5        5     2,3
 

In run mode as follows
 
Month    Dropdownlist
 
Year      Dropdownlist
 
Facid     Dropdwonlist    (Facid is to retrieved from the Btfac table)
 

Example as follows
 
Facid  1,3,5  (Dropdownlist)
 
when i click the dropdownlist i want to show the respective facname in the label.
 
i want the output as follows
 

Facid 1,3,5 (Dropdwonlist) 

G Sekar

R Kumar
V Gopi
 

for that how can i do using c sharp.
 
Note it is web application.
 
Regards,