[Solved] UserControl or storyboard inside treeviewitem

[Mitch]

I need to be able to start and stop a usercontrol or storyboard background from code for a particular radtreeviewitem when I want to alert the user that something has happened for a contact.

I have a databound radtreeview for a contact list.

<!-- data template for the Contact object-->
        <telerik:HierarchicalDataTemplate x:Name="ContactTemplate" telerik:ContainerBinding.ContainerBindings="{StaticResource BindingsCollection}" >
            <local:ContactBackgroundControl x:Name="ContactBlinker" >
                <StackPanel x:Name="ContactContent" Orientation="Horizontal">
                    <telerikNavigation:RadContextMenu.ContextMenu>
                        <telerikNavigation:RadContextMenu x:Name="ContactContextMenu" ItemClick="RadMenuItem_Click" Opened="ContactContextMenu_Opened">
                            <telerikNavigation:RadMenuItem Header="Send IM"  Tag="{Binding SIPURL}" />
                            <telerikNavigation:RadMenuItem Header="Start Livemeeting" Tag="{Binding SIPURL}"  />
                        </telerikNavigation:RadContextMenu>
                    </telerikNavigation:RadContextMenu.ContextMenu>
                    <Image Source="{Binding CurrentPresence, Converter={StaticResource PresenceConverter}}" Margin="0, 0, 5, 0"/>
                    <TextBlock Text="{Binding ContactName}" Margin="0, 0, 0, 0" />
                </StackPanel>
            </local:ContactBackgroundControl>
        </telerik:HierarchicalDataTemplate>

Inside the datatemplate I have a usercontrol I have created (ContactBackgroundControl) which is just a stackpanel with a background that goes from transperent to a color and back again.

When I try the code below, I get an error "Reference is not a valid visual DependencyObject" refering to when I do the FindChildByType call searching for the type "ContactBackgroundControl". I have also tried the type "UserControl", but that results in the same exact error.

public void SetContactBlinking(string sipuri)
        {
            //iterate thorugh each group, and each groups contacts in the treeview
            foreach (ContactGroup group in OCSContactsTreeView.Items)
            {
                int ContactIndex = 0;
                foreach (Contacts_ contact in group.Contacts_)
                {
                    //if the contact matches the sent sipuri, get the treeview item and set blinking
                    if(contact.SIPURL == sipuri)
                    {
                        RadTreeViewItem TVItem = (RadTreeViewItem)(OCSContactsTreeView.ItemContainerGenerator.ContainerFromIndex(ContactIndex));
                        //get the instance of the contactbackgroundcontrol and start the storyboard
                        ContactBackgroundControl Control = TVItem.Template.FindChildByType<ContactBackgroundControl>();
                        Control.BlinkContact.Begin();
                    }

                    ContactIndex++;
                }

            }
        }

Is there any way to get a reference to the particular usercontrol inside the radtreeview item so I can start or stop the usercontrol storyboard? Or is there some better method to pull off an effect like this?

Thanks!

[Tina Stancheva]

Hi Mitch,

You can get the ContactBackgroundControl through the FindChildByType() method, like so:

ContactBackgroundControl Control = TVItem.FindChildByType<ContactBackgroundControl>();

Please give it a try and let me know if it works for you.

Greetings,
Tina Stancheva
the Telerik team

[pat]

This reply seems to exactly repeat the code in the question.  What was the fix?

[Tina Stancheva]

Hi Pat,

Mitch was looking for his custom control in the RadTreeViewItem.Template:

ContactBackgroundControl Control = TVItem.Template.FindChildByType<ContactBackgroundControl>();

However, the Template property is not a visual DependancyObject and therefore the FindChildByType() method cannot be used with it.

My suggestion was to use the FindChildByType() method directly on the RadTreeViewItem:

ContactBackgroundControl Control = TVItem.FindChildByType<ContactBackgroundControl>();

Are you facing similar issues? If so, can you please elaborate on them as we might be able to provide you with a better solution?

Regards,
Tina Stancheva
the Telerik team