I would like to know how ot update the data of the dojo.dijit.tree component dynamically. At the moment I'm creating the tree using dojo.data.ItemFileReadStore and dijit.tree.ForestStoreModel. Once I create the tree, I would like to reload it periodically with new JSON data.

This i开发者_JAVA百科s how I create the tree at the moment:

<div dojoType="dojo.data.ItemFileReadStore" jsId="myStore" url=getJSONResult></div>

<div dojoType="dijit.tree.ForestStoreModel" jsId="myModel" store="myStore" query="{type:'cat'}" rootId="myRoot" rootLabel="Data" childrenAttrs="children"></div>

<div dojoType="dijit.Tree" model="myModel" labelAttr="sname" label="Data" />

Thanks in advance.

Explicitly you "can't", but that doesn't mean you can't hack things to pieces and die trying.

refreshTree : function(){
    dijit.byId("myTree").dndController.selectNone(); // As per the answer below     
    // Credit to this discussion: http://mail.dojotoolkit.org/pipermail/dojo-interest/2010-April/045180.html
    // Close the store (So that the store will do a new fetch()).
    dijit.byId("myTree").model.store.clearOnClose = true;
    dijit.byId("myTree").model.store.close();

    // Completely delete every node from the dijit.Tree     
    dijit.byId("myTree")._itemNodesMap = {};
    dijit.byId("myTree").rootNode.state = "UNCHECKED";
    dijit.byId("myTree").model.root.children = null;

    // Destroy the widget
    dijit.byId("myTree").rootNode.destroyRecursive();

    // Recreate the model, (with the model again)
    dijit.byId("myTree").model.constructor(dijit.byId("myTree").model)

    // Rebuild the tree
    dijit.byId("myTree").postMixInProperties();
    dijit.byId("myTree")._load();

},

This will refresh your Tree.

Here's a problem with Layke's solution (which otherwise does work) found by pre-production testing for a commercial website.

Case 1:

Create & populate a tree.
Click on a node to select.
Execute refreshTree as in Layke's solution.
Click on a node, get error "this.labelNode is undefined".

Now start again, case 2:

Create & populate a tree.
Click on a node to select.
Ctrl-click on the previously selected node.
Execute refreshTree as in Layke's solution.
Click on a node, no error.

The stored selection references to the first selection are being used to undo the selection attributes (background color, etc.) when the second selection is made. Unfortunately, the referred-to objects are now in the bit-bucket. The modified code appears to be production-ready, i.e. hasn't failed any pre-production tests.

The solution is to put:

Tree.dndController.selectNone();

prior to first line of Layke's refreshTree solution above.

In response to meta suggestions, here it is:

refreshTree : function() {
    // Destruct the references to any selected nodes so that 
    // the refreshed tree will not attempt to unselect destructed nodes
    // when a new selection is made.
    // These references are contained in Tree.selectedItem,
    // Tree.selectedItems, Tree.selectedNode, and Tree.selectedNodes.
    Tree.dndController.selectNone();

    Tree.model.store.clearOnClose = true;
    Tree.model.store.close();

    // Completely delete every node from the dijit.Tree     
    Tree._itemNodesMap = {};
    Tree.rootNode.state = "UNCHECKED";
    Tree.model.root.children = null;

    // Destroy the widget
    Tree.rootNode.destroyRecursive();

    // Recreate the model, (with the model again)
    Tree.model.constructor(dijit.byId("myTree").model)

    // Rebuild the tree
    Tree.postMixInProperties();
    Tree._load();

}

Thanks for this function, works great in my tree.

A notice to those who are new to dojo (like me)... After creation of the tree, it is needed to extend the tree with the refresh function:

dojo.extend(dijit.Tree, {
    refresh: function() {
        this.dndController.selectNone();
        //...
    }
});

Then you can call the function with:

dijit.byId('myTree').refresh();

Updating your store will automatically update your tree!

You need a FileWriteStore, which gives you the ability to modify your data.
Use the store to fetch the items you want to update via query.
Update each item returned.

Then save the store and the tree will update.

FileWriteStore.fetch({
    query: { color: "red" },
    onComplete: function(items){
        for (var i = 0; i < items.length; i++){
            FileWriteStore.setValue(items[i], "color", "green");
        }
        FileWriteStore.save();              
    }
});

Layke's solution did not work for me. I am using dojo 1.9.1. My store is of type "ItemFileWriteStore" and the model of type "TreeStoreModel".

myStore = new ItemFileWriteStore({
    url : "../jaxrs/group/tree"
});

itemModel = new TreeStoreModel({
    store : myStore,
    query : {
        id : "0"
    }
});
parser.parse();

This works for me:

var tree = dijit.byId('myTree');
tree.dndController.selectNone(); 
tree._itemNodesMap = {};
tree.model.root = null;
tree.model.store.clearOnClose = true;
tree.model.store.urlPreventCache = true;
tree.model.store.revert(); 
tree.model.store.close();
tree.rootNode.state = "UNCHECKED";
if (tree.rootNode) {
    tree.rootNode.destroyRecursive();
}
tree.postMixInProperties();
tree._load();

While going through these answers I've built my own method to update specific nodes once at a time and NOT need the refresh.

_refreshNodeMapping: function (newNodeData) {

    if(!this._itemNodesMap[newNodeData.identity]) return;

    var nodeMapToRefresh = this._itemNodesMap[newNodeData.identity][0].item;
    var domNode = this._itemNodesMap[newNodeData.identity][0].domNode;

    //For every updated value, reset the old ones
    for(var val in newNodeData)
    {
        nodeMapToRefresh[val] = newNodeData[val];

        if(val == 'label')
        {
            domNode.innerHTML = newNodeData[val];
        }
    }  
}

Not supported at present. See here.