I'd like to add a multiple select drop down filter to one of my list/grid views (it's being loaded from a foreign key), i.e. I'd like to subset the list using more than one foreign key value

Does anyone have an idea (just need a starting point) on how one could go about doing that?

Thanks!
Dave

Hi Dave,

JDom? I'm eventually going to be doing this for a product attributes filter in the next month or s as part of a shopping cart extension. I haven't given it any more thought other than my presumption to begin by looking at the JDom class responsible for populating the filters options & markup then extend it to allow multiple selection.

Some changes will need to be made to the sql query to accommodate how you would like it to behave: are the conditions to be chained by 'OR' / 'AND' operators for example... Anyway, let us know how it goes and if you need anything else. Hope it helps a little!

Gez

You will need to write both in JDom and in the component model.

JDom can display the control, but its role is limited to this.

JDom :
Extends a normal combo to a multi-checkable list.
-> html.form.input.select.multi (new class)

Override only few things to make a control sending an ARRAY in post.

In Component list model:
(Write the maximum you can in the super class)

In this list model in general, receive this array and set the filter state var, this is already done automatically :
Change the filter type to 'array' in the list model constructor.(not tested, but should work)

Then in prepareQuery, create the SQL filter.
For this particular purpose, a super-function could be awesome. (Such as 'propagateAccesses' SQL creation)

Hope it helps.

Also...

When you reload the page, the filter must be able to display the current selected values.
This should be done automatically, but I never tested it with arrays.

If somebody is trying all this I would really enjoy to have your reviews.

Thanks again Gez for your help.