I am trying to find the most efficient method for designing. We have
several pages with dependent dropdowns. Currently what we do is
whenever user selects item in one dropdown then we go to the database
to re-populate the values in the second and third dropdown. And when
user selects the second dropdown re-populate the third one by going to
the database again. Obviously this is not the efficient way. So I
decided to re-code that. I found out the following alternatives:
1. Store all the data of the three dropdowns into three dataset which
is further stored in the cache. This is done only once when the
webserver is started since the data to be shown in the dropdown is
just readonly. Bind the first dropdown to the first dataset. Whenever
user selects any item the first dropdown filter the second dataset
that is in the cache and show the corresponding data in the second
dropdown. and so on
2. do as above but store in the cache three xmlDataDocument objects
instead of dataset and use xpath to get the corresponding data.
3. Use client side javascript and xml just as in this example.
http://www.codeproject.com/aspnet/masterdetailddl.asp
This solution works on Netscape 6.0+ and IF 5.0+ which is fine.

The data in the dropdown is very less i.e. about 10 in the first 25 in
the second and 60 in the last
I did some tests myself and found that the 2nd one took the shortest
time.
Does anybody know of any other way or have any comments.

I am thinking of sessions also, but since this data is going to be the
same for all the users doesn't make sense in terms of scalability.