CompoundField and ArrayField


How to make custom fields: a list of some default field type, a compound of a two or more default fields.


Install the CompoundField extension into you Products folder.

List of fields - ArrayField

Assume you want to have content type where the user can provide one or more files. Its easy by making the type folderish. But for some use-cases this is to heavy or to difficult, you want the user to use a form for those files.

You could say, ok, up to 5 files is enough and model 5 file fields into your class. Not very elegant, huh?

The easiest way is to to use the UML multiplicity feature on your attribute aka field of the class. If you want to enable unlimited attachments use multiplicity *. Or choose a number like 5, as in our above example.

You can set the initial size of the array by using the tagged value array:size to python:10 for example. Prefixed with array: you can access also the label array:widget:label of it and so on. If you prefer the EnhancedArrayWidget you need to add an tagged value imports from Products.Compoundfield.EnhancedArrayWidget import EnhancedArrayWidget to your class and set on the attribute the tagged value array:widget:type to EnhanceArrayWidget.

Custom Fields compounds - CompoundField

With ArchGenXML you can create compounds of fields from existing fields. Such a set of fields behaves almost like a normal field. To create such a compounded field create a new class and give it the stereotype <<field>>

Now add attributes to it like you would do on a content type class. You can use almost every field type, just some special fields, mostyl those acting as a proxy without own storage, wont work (such as ReferenceField or AttachementField).

For example we create a PointField consisting out of two FloatFields by just adding a x and y attribute of type float.

To use the new field create a fresh content class and name it Polygon. Take a dependency arrow pointing from your Polygon class to the field class. This ensures it gets imported!

Next add an attribute points to the class. The type of the new points attribute is PointsField. Now to make it a polygon give it a multiplicity of * and you are done: You have a list of Points as one field.