[Solved] Changing the data loaded in the node when ExpandMode=WebService (WCF)

[relper]

I’m using a ReadTreeView with ExpandMode set to WebService. When I expand the node, I use NodePopulating to pass the proper parameters. Then the web service method is called and returns the data to be loaded on the tree. The problem is that the data returned contains more information than just Text and Value which seem to be mapped automatically from members with the same name. But if this data doesn’t contain properties Text/Value or I want to load the tree node custom attributes collection with other values, how do I do that?

By the way, I’m using WCF and the return type is defined in a DataContract class, as in your example of the KB article at http://www.telerik.com/community/code-library/submission/b311D-bcaeek.aspx.

Thanks!

[T. Tsonev]

Hello Ricardo,

We have updated the KB article to include custom attributes. The changes on the server-side are trivial - all we need to do is to add a dictionary property to the RadTreeNodeInfo class:

[DataMember]
public IDictionary<string, object> Attributes
{
    get { return _attributes; }
    set { _attributes = value; }
}

On the client-side things are a bit more complicated. As this MSDN article explains, the DataContractJsonSerializer serializes dictionaries as arrays of key/value pairs, instead of JSON objects. Therefore we need a helper routine on the client to help us get the attribute values:

function nodePopulated(sender, eventArgs)
{
    var childNodes = eventArgs.get_node().get_nodes();
    for (var i = 0; i < childNodes.get_count(); i++)
    {
        var node = childNodes.getNode(i);
        var attributeValue = getAttributeValue(node.get_attributes(), "TestAttribute");
        node.set_text(node.get_text() + "[" + attributeValue + "]");
    }
}

function getAttributeValue(attributeCollection, key)
{
    // The DataContractJsonSerializer serializes the dictionary as an
    // array of key/value pairs and we cannot use the attributeCollection
    // methods directly.
    for (var i = 0; i < attributeCollection.get_count(); i++)
    {
        var keyValuePair = attributeCollection.getAttribute(i);
        if (keyValuePair.Key == key)
        {
            return keyValuePair.Value;
        }
    }

    return null;
}

I hope this helps.

Best wishes,
Tsvetomir Tsonev
the Telerik team

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[relper]

Thanks Tsvetomir! This will definitely help.