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So i have a task where I am create an application for the user to select the name of a tree, and select 2 different years ( like 1920 and 1980) and then the app will show how many trees there were of that type in those 2 years. Im quite the beginner in programming, but really eager to learn! The difficulty on this shoudln't be too high, so I tried a little with dropdownlists, but couldn't quite figure out how to link them :/

This is the info i was given..

Trees   1915 1950 1970 1990 1992 2000
Furu     20   31   53   89   102 117
Gran     23   39   72   89   92  99
Lauvtre  4    6    8    12   15  18

Is ddl even the right solution for this?

Thanks for any help! =)
Posted 21-May-13 2:29am
V. 21-May-13 8:37am
You're not clear. Why would you want to select 2 years and not 5 or 10 ? Or do you want to select the number of trees between year 1 and year 2 ? What dropdown list should be 'linked', what do you mean by that? Best example of linked lists are country, city, street options eg. it is indeed not that difficult.
Twinniez 21-May-13 8:40am
What i want is for the user to be able to select 2 of the years listed above and 1 of the tree types, and then the app will print how many trees there were of that exact tree in both of those years
lukeer 21-May-13 9:23am
That still doesn't link the lists. It's just 3 lists containing trees, firstYears and secondYears.

Except there should be some extra logic that perhaps prevents using the same year twice, second must be later than first, and so on. Is there some such condition?
Zafar Sultan 21-May-13 9:29am
So what is the problem? What have you tried so far?
Twinniez 21-May-13 9:34am
My problem now is that when i select the tree "furu" and the year "1950" how do i make it extraxct the info for how many there were of that exact tree that exact year?
NJRoha 21-May-13 16:25pm
Since you did not provide much detail, I would assume you are trying to filter the data based on the tree and year selection and find out what would be the tree count for the selected tree and year combination. To do so you need to maintain the x-ref between tree and year for counts. Once you do that, you can query the data once selection is being made. You can either store the values in DataTables in DataSet so that you can query them easyly and in-memory.

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