Problem with MVC TreeView LoadOnDemand

It will be great if i get any feedback from Telerik Support centre or anyone in the forum who has faced this problem.  The MVC TreeView code snippet for Load on Demand in Razor is not working. 

So is there any resolution for this? I am experiencing the exact same issue. Have tried the sample application from the latest release and am getting the same error.

For the record, I am using very similar code in an MVC project using Web Forms View Engine without a problem. The problem only occurs within a Razor view.

Compilation Error

Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately.

Compiler Error Message: CS1593: Delegate 'System.Action<Telerik.Web.Mvc.UI.NavigationBindingFactory<Telerik.Web.Mvc.UI.TreeViewItem>>' does not take 2 arguments

Source Error:

Line 9: .TreeView() Line 10: .Name("OrganizationTreeView") Line 11: .BindTo(Model, (item, org) => Line 12: { Line 13: // bind initial data - can be omitted if there is none

Would be great if Telerik can address either the issue or what I've done wrong.

Hi Alec,

 We need a sample project which reproduces this problem as we are not sure what may be causing it.

Regards,
Atanas Korchev
the Telerik team

We were able to solve the problem, more on that below. I will also provide a sample sometime this weekend that shows the problem (if I can reproduce outside our project).

Problem
The TreeView controls BindTo() method was not finding the right signature. We have set our model to:

@model IEnumerable<OurViewModel>

and were trying to use the BindTo(IEnumerable<T> Model, Action <TreeViewItem, T>) signature. For whatever reason, this would not work. It always tried to use the BindTo(IEnumerable Model, Action<NavigationBindingFactory<TreeViewItem>> action) signature.

To get around this, we simply moved it over to BindTo<T> to force it to use the signature we wanted. Really not sure why this is happening. 

Alec,

Can you show some code or more info. I have the same problem

I have this code:

Html.Telerik().TreeView()
        .Name("TreeView")
        .BindTo<CategoryModel>(Model, mappings => 
        {
            mappings.For<CategoryModel>(binding => binding
                    .ItemDataBound((item, category) =>
                    {
                        item.Text = category.Name;
                    })
                    .Children(category => category.ParentCategoryID));
            
            mappings.For<CategoryModel>(binding => binding
                    .ItemDataBound((item, cat) =>
                    {
                        item.Text = cat.Name;
                    }));
        }).Render();

and also I get mappings doesnt contain method or extension "For"

Thanks

Alex.

sasho in your case your problem is the
part.

If you use the generic form of the method the second parameter it expects should be:
(item, category) =>

If you want to use the mapping way use it like this:

Hey Alec, could you explain a bit more in detail how did you solve your problem, cause I have exactly the same problem as InfoSeeker provided.

Thanks.

Hi.

I started using Telerik mvc controls recently and encountered the same issue with TreeView biding to a Model.
Sample code stated that BindTo method takes IEnumerable<T> as a first argument.
But for the new API, it takes IEnumerable interface instead.
So, declaring your model as IEnumerable resolve the issue:

@model System.Collections.IEnumerable

@(Html.Telerik().TreeView().Name("TreeView")
    .BindTo(Model, mappings => {
        mappings.For<Employee>((n) => {
            n.ItemDataBound((i, e) =>
            {
                i.Value = e.Id.ToString();
                i.Text = e.Name;
            })
            .Children(e => e.Employees);
        });
    })
)