RadComboBox RadTreeView ServerSide

[Cristian Malinescu]

Hi

I'm trying to insert in the server side the nodes of a treeview as in the sample 

http://demos.telerik.com/aspnet-ajax/treeview/examples/functionality/treeviewcombobox/defaultcs.aspx

but my code fails as there is no treeview widget object available  

aspx code:

 

<td align = "left">

 

 

 

  <telerik:RadComboBox id = "_Fields_ComboBox_" EmptyMessage = "Choose a field..." runat = "server">

 

 

 

    <ItemTemplate>

 

 

 

       <div id = "_Fields_TreeView_Container_">

 

 

 

         <telerik:RadTreeView id = "_Fields_TreeView_" runat = "server">
...

and VB

 

Dim

 

ref As Object = _Fields_ComboBox_.Items(0).FindControl("_Fields_TreeView_")

 

 

 

will generate

[ArgumentOutOfRangeException: Index was out of range. Must be non-negative and less than the size of the collection.
Parameter name: index]
   System.Collections.ArrayList.get_Item(Int32 index) +7487944
   System.Web.UI.StateManagedCollection.System.Collections.IList.get_Item(Int32 index) +12
   Telerik.Web.UI.ControlItemCollection.get_Item(Int32 index) +48
   Telerik.Web.UI.RadComboBoxItemCollection.get_Item(Int32 index) +36


It looks to me like a candiate for a bug ...?
I use a lot in the server to fill treeview widgets with nodes with no problems; this is the single case where I try to do the same
in a treeview wrapped as an itemtemplate for a combobox.

The provided sample is not covering this scenario; maybe will be a good idea to add it.

Cheers,
Cris

Update:

I removed the server side code and I put for testing a declarative list of nodes in the <Nodes/> section - as per example;
my combo dosn't display any of these items - it is always empty.  The RadControls version we use is Q1 2010.
 

 

[Veronica]

Hello Cristian Malinescu,

I made a test project to test your scenario.

After you add the RadTreeView as an ItemTemplate in your RadComboBox I can not see but I think you are missing an Item in your RadComboBox:

<telerik:RadComboBox ID="RadComboBox1" runat="server" Height="140px" Width="215px"
                ShowToggleImage="True" Style="vertical-align: middle;" OnClientDropDownOpened="OnClientDropDownOpenedHandler"
                EmptyMessage="Choose a destination" ExpandAnimation-Type="None" CollapseAnimation-Type="None">
                <ItemTemplate>
                    <div id="div1">
                        <telerik:RadTreeView runat="server" ID="RadTreeView1" OnClientNodeClicking="nodeClicking" Height="138px" Width="212px">
                        </telerik:RadTreeView>
                    </div>
                </ItemTemplate>
                <Items>
                    <telerik:RadComboBoxItem Text="" />
                </Items>
            </telerik:RadComboBox>

This will cause an ArgumentOutOfRangeException when you try to index the Items of the RadComboBox as this:

Dim tree As RadTreeView = DirectCast(RadComboBox1.Items(0).FindControl("RadTreeView1"), RadTreeView)

Find my project in the attached .zip file and please let me know if this was helpful.

Regards,
Veronica Milcheva
the Telerik team

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[Cristian Malinescu]

Thank you Veronica,

It is right; all my items are server side dynamically created; the same technique works without problems for a not combobox embedded treeview; like this:

aspx:

 

<telerik:RadComboBox id = "_Employee_ComboBox_"

 

 

EmptyMessage = "Choose an employee..."

 

 

runat = "server">

 

 

</telerik:RadComboBox>

 

code-behind:

Dim

 

comboBoxItem As RadComboBoxItem

 

 

For Each employee As Employee In employees

 

comboBoxItem =

New RadComboBoxItem()

 

comboBoxItem.Text = employee.LastName &

", " & employee.FirstName

 

comboBoxItem.Value =

CType(employee.ID, String)

 

_Employee_ComboBox_.Items.Add(comboBoxItem)

 

Next

 

So, what I think the code flow of the combobox embedded treeview *forgets* (leaves undefined) about the parent/child widgets relationship; this is a bug. Debugging I see that the items collection of the combobox is empty.

[Veronica]

Hello Cristian Malinescu,

Could you please send me the full code you are using so we can be able to help you?

Thank you!

Greetings,
Veronica Milcheva
the Telerik team

Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking system and vote to affect the priority of the items.

[Cristian Malinescu]

Hi Veronica and thanks for the assistance.

The code we talked about is not so much relevant as I got the working internals of the radcombo/radtree partnership; the tree widget is expected to be a context provider(value/text) for the default - on purpose declared empty item of the combo widget.

The problem I'm facing now is this one, can you help with it?

http://www.telerik.com/community/forums/aspnet-ajax/combobox/radcombobox-radtreeview-item-server-side-the-combobox-doesn-t-resize-when-tree-expands.aspx

Also, as a suggestion - I think there is still work to be done for the combo/tree integration as the scenario presented in the sample
looks to me as more suited to pure declarative scenarios - for cases when the whole content is dynamic I think lots of work has to be done on the sides - in the browser to resize the radcombo so that no scrolling would be required from the user perspective.

Cheers,
Cris

[Veronica]

Hi Cristian Malinescu,

To be able to resize the RadComboBox and no H/V scrollbars to appear you may subscribe to the OnClientNodeExpanding event like this:

function nodeExpanding(sender, eventArgs) {
            var $ = $telerik.$;
            var combo = $find("<%= RadComboBox1.ClientID %>");
            var dropDownElement = combo.get_dropDownElement();
            var treeDiv = document.getElementById("RadComboBox1_i0_RadTreeView1");
            $(".rcbScroll", dropDownElement).height(treeDiv.style.height);
        }

In the function above we are getting the height of the div tag which contains the RadTreeView. After that we are setting the height of the RadComboBox to this height.

Find the full code in the attached .zip file.

Hope this helps. 
 
Sincerely yours,
Veronica Milcheva
the Telerik team

Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking system and vote to affect the priority of the items.

[Prahlad]

hii,

I am trying to find my treeview contol

 Telerik.Web.UI.RadTreeView treeView = (Telerik.Web.UI.RadTreeView)rcbParent.Items[0].FindControl("rtvParent");
 then i am getting error
Object reference not set to an instance of an object.

please help me to solve this...
thanks in Advance

[Ivan Danchev]

Hello,

Can you please elaborate more on what controls you have on your page and if they are nested what is the hierarchy? It would be helpful if you could post the content of your .aspx file, which would give us an idea which control you are trying to access.

Regards,
Ivan Danchev
Telerik