cascading dropdown box when the preceding value is NULL

[Malcolm]

Greetings,

I need to help the user to select the right value by narrowing their choice using a series of cascading dropdown boxes, until they reach a unique record to select.

The three fields are Level 1, Level 2 and Level 3 - nice and simple so far. The cascade option in the dropdown box works like a treat - until it comes across a null value in Level 2. A very few rows (of the hundreds) only have a value in Level 1 - because the level 1 defines them as unique.

In the above case, the dropdown box for Level 3 has only a NULL to base its selection on, so there is no value - and the UX doesn't accept that. So the user can't make a selection.

Can I somehow 'disable' the lower level dropdowns, and get the final one to point to the last 'not-null' value? How have others handled this issue?

Many thanks

Malcolm

[lgrupido]

The easiest solution is to make sure the scenario you are experiencing doesn't happen. Fix the data so there is ALWAYS a Level 2 for every Level 1, even if the Level 2 value is just a placeholder value.

If you can't do that, then you are going to have to buffer it with some scripting and you likely won't be able to use the built in cascading drop down method.

[WebDesignShop]

You would need to add custom script to return the number of sub records. You can call the same function each time, passing in the table and field to query. If the return record set has no records, then disable the other controls. There is action javascript to return records based on a form field.

[Malcolm]

Thanks both, in this case the 'easy out' is probably the most practical solution - I just hadn't thought of it! Thx again