dijit.tree.ObjectStoreModel

since:V1.8

Introduction

The ObjectStoreModel implements a dijit.tree.Model to connect a dijit.Tree to a dojo.store.

The dojo.store must implement it's own getChildren() method.

If the store implements the Observable API implemented in dojo.store.Observable, then it will be leveraged to reflect store updates to the tree.

To support drag and drop, besides implementing getChildren() and Observable, the store must support the parent option to put(). And in order to have child elements ordered according to how the user dropped them, put() must support the before option.

Example

require([
    "dojo/aspect", "dojo/_base/window", "dojo/store/Memory", "dojo/store/Observable",
    "dijit/Tree", "dijit/tree/ObjectStoreModel", "dijit/tree/dndSource",
    "dojo/domReady!"
], function(aspect, win, Memory, Observable, Tree, ObjectStoreModel, dndSource){

    // Create test store.
    store = new Memory({
        data: [
            { id: 'world', name:'The earth', type:'planet', population: '6 billion'},
            { id: 'AF', name:'Africa', type:'continent', population:'900 million', area: '30,221,532 sq km',
                    timezone: '-1 UTC to +4 UTC', parent: 'world'},
                { id: 'EG', name:'Egypt', type:'country', parent: 'AF' },
                { id: 'KE', name:'Kenya', type:'country', parent: 'AF' },
                    { id: 'Nairobi', name:'Nairobi', type:'city', parent: 'KE' },
                    { id: 'Mombasa', name:'Mombasa', type:'city', parent: 'KE' },
                { id: 'SD', name:'Sudan', type:'country', parent: 'AF' },
                    { id: 'Khartoum', name:'Khartoum', type:'city', parent: 'SD' },
            { id: 'AS', name:'Asia', type:'continent', parent: 'world' },
                { id: 'CN', name:'China', type:'country', parent: 'AS' },
                { id: 'IN', name:'India', type:'country', parent: 'AS' },
                { id: 'RU', name:'Russia', type:'country', parent: 'AS' },
                { id: 'MN', name:'Mongolia', type:'country', parent: 'AS' },
            { id: 'OC', name:'Oceania', type:'continent', population:'21 million', parent: 'world'},
                { id: 'AU', name:'Australia', type:'country', population:'21 million', parent: 'OC'},
            { id: 'EU', name:'Europe', type:'continent', parent: 'world' },
                { id: 'DE', name:'Germany', type:'country', parent: 'EU' },
                { id: 'FR', name:'France', type:'country', parent: 'EU' },
                { id: 'ES', name:'Spain', type:'country', parent: 'EU' },
                { id: 'IT', name:'Italy', type:'country', parent: 'EU' },
            { id: 'NA', name:'North America', type:'continent', parent: 'world' },
                { id: 'MX', name:'Mexico', type:'country',  population:'108 million', area:'1,972,550 sq km',
                        parent: 'NA' },
                    { id: 'Mexico City', name:'Mexico City', type:'city', population:'19 million', timezone:'-6 UTC', parent: 'MX'},
                    { id: 'Guadalajara', name:'Guadalajara', type:'city', population:'4 million', timezone:'-6 UTC', parent: 'MX' },
                { id: 'CA', name:'Canada', type:'country',  population:'33 million', area:'9,984,670 sq km', parent: 'NA' },
                    { id: 'Ottawa', name:'Ottawa', type:'city', population:'0.9 million', timezone:'-5 UTC', parent: 'CA'},
                    { id: 'Toronto', name:'Toronto', type:'city', population:'2.5 million', timezone:'-5 UTC', parent: 'CA' },
                { id: 'US', name:'United States of America', type:'country', parent: 'NA' },
            { id: 'SA', name:'South America', type:'continent', parent: 'world' },
                { id: 'BR', name:'Brazil', type:'country', population:'186 million', parent: 'SA' },
                { id: 'AR', name:'Argentina', type:'country', population:'40 million', parent: 'SA' }
        ]
    });

    // Since dojo.store.Memory doesn't have various store methods we need, we have to add them manually
    store.getChildren = function(object){
        // Add a getChildren() method to store for the data model where
        // children objects point to their parent (aka relational model)
        return this.query({parent: this.getIdentity(object)});
    };
    aspect.around(store, "put", function(originalPut){
        // To support DnD, the store must support put(child, {parent: parent}).
        // Since our store is relational, that just amounts to setting child.parent
        // to the parent's id.
        return function(obj, options){
            if(options && options.parent){
                obj.parent = options.parent.id;
            }
            return originalPut.call(store, obj, options);
        }
    });

    // Wrap the store in Observable so that updates to the store are reflected to the Tree
    store = new Observable(store);

    // Create the model and tree
    model = new ObjectStoreModel({store: store, query: {id: 'world'}});
    tree = new Tree({
        model: model,
        dndController: dndSource
    }).placeAt(win.body());
});

See Also