LoadOnDemand force notification for IsLoadOnDemandEnabled

[Shawn]

I am trying to use a TreeView to show data read from a webservice.  However, I have a special requirement.  Normally the presence of the ExpandCollapseIndicator is determined by the return value of CanExecute function of the LoadOnDemandCommand.  A custom item template would include the ExpandCollapseIndicator and bind its IsLoadOnDemandEnabledProperty to TreeViewDataItem.IsLoadOnDemandEnabled.  This works fine if the ability to expand/collapse remains constant. I need the ability to change the value of TreeViewDataItem.IsLoadOnDemandEnabled AFTER the tree node has been initialized.  Normally, I would just do OnPropertyChanged(nameof(IsLoadOnDemandEnabled)) but I do not have access to that since TreeViewDataItem is a wrapper around my own data model class.  I do not have access to TreeViewDataItem.

 

So how can I force an update to the ExpandCollapseIndicator AFTER the tree node has been initialized as my CanExecute function of LoadOnDemandCommand will now return a different value?

[Yana]

Hi Shawn,

Thank you for providing the scenario details.

Would it possible, in this case, to add a boolean property to your business object indicating whether load-on-demand should be enabled for this item?  Using this property you could switch the TreeViewItem IsLoadOnDemandEnabled value through binding inside the TreeView ItemTemplate.

What do you think of such an approach, would it work for you?

Regards,
Yana
Progress Telerik