Delegates

Release:master
Date:December 02, 2014

Delegates are a cornerstone of the Qt model/delegate/view framework. A delegate is used to display and edit data from a model.

In the Camelot framework, every field of an Entity has an associated delegate that specifies how the field will be displayed and edited. When a new form or table is constructed, the delegates of all fields on the form or table will construct editors for their fields and fill them with data from the model. When the data has been edited in the form, the delegates will take care of updating the model with the new data.

All Camelot delegates are subclasses of QAbstractItemDelegate.

The PyQT website provides detailed information the differenct classes involved in the model/delegate/view framework.

Specifying delegates

The use of a specific delegate can be forced by using the delegate field attribute. Suppose rating is a field of type integer, then it can be forced to be visualized as stars:

from camelot.view.controls import delegates

class Movie( Entity ):
    title = Column( Unicode(50) )
    rating = Column( Integer )

    class Admin( EntityAdmin ):
        list_display = ['title', 'rating']
        field_attributes = {'rating':{'delegate':delegates.StarDelegate}}

The above code will result in:

doc/../_static/editors/StarEditor_editable.png

If no delegate field attribute is given, a default one will be taken depending on the sqlalchemy field type.

All available delegates can be found in camelot.view.controls.delegates

Available delegates