Expand all nodes?

[KevinMc]

Is there anyway to set the default state of a treeview to expanded when it is loaded?

[Veselin Vasilev]

Hi KevinMc,

You can call the ExpandAllNodes() server-side method of the treeview:

RadTreeView1.ExpandAllNodes();

Kind regards,
Veskoni
the Telerik team

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[KevinMc]

It is a treeview in a combobox. If i put this in the page_load method i get null reference exception probably because it is not bound to the datasource yet.

RadTreeView cats = (RadTreeView)comboCategories.FindControl("treeCategories");
cats.ExpandAllNodes();

Where should i set the expandallnodes at in this scenario?

[Veselin Vasilev]

Hello KevinMc,

You need to use this code:

RadTreeView cats = (RadTreeView)comboCategories.Items[0].FindControl("treeCategories");
cats.ExpandAllNodes();

Now it should find the treeview properly.

Regards,
Veskoni
the Telerik team

Instantly find answers to your questions at the new Telerik Support Center

[KevinMc]

Adding items on findcontrol corrects the null reference exception but the treeview still is not expanded.

[Veselin Vasilev]

Hi KevinMc,

Here is another idea: subscribe to the OnClientDropDownOpening event of the combobox, find the treeview, loop thought its nodes and expand them:

function OnClientDropDownOpeningHandler(sender, eventArgs)
{
    var tree = $find('<%= RadComboBox1.Items[0].FindControl("RadTreeView1").ClientID %>');

    var nodes = tree.get_allNodes();

   for (var i = 0; i < nodes.length; i++)
   {
       if (nodes[i].get_nodes() != null)
       {
           nodes[i].expand();
       }
   }
}

Kind regards,
Veskoni
the Telerik team

Instantly find answers to your questions at the new Telerik Support Center