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Nested Treeview Issues

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Wayne
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Wayne asked on 18 Jul 2014, 10:41 PM
My company is considering purchasing several licenses of Kendo UI Professional and UI for ASP.NET MVC.  I am using MVC 5 and the latest version of UI for ASP.NET MVC.  I am working with hierarchical data.   I am attempting to create the TreeView in the _Layout view and populate it with urls or action links.

My current code:

In the _Layout View:

@Html.Partial("_ProductTree")

"_ProductTree" Partial View

@(Html.Kendo().TreeView().Name("ProductTree")
    .DataSource(d => d
        .Model(m => m
            .Id("ProductId")
            .HasChildren("Categories"))
    .Read(r => r.Action("_ProductTree", "Home")))
    .DataTextField("ProductName"))

Action Method:

        [ActionName("_ProductTree")]
        public JsonResult GetProductTree()
        {
            var products = _productBusinessService.GetProducts();

            var result = products.Select(c => new
            {
                c.ProductID,
                c.ProductName,
                Categories= c.Categories.Any()
            }).OrderBy(t => t.ProductName);

            return Json(result, JsonRequestBehavior.AllowGet);
        }

I am having a number of issues:

1.  When I expand a parent node that has children, the TreeView is hitting the action method and appending the entire tree to the child, instead of just displaying the children.
2.  I need to be able to nest the TreeView two-deep, for example Product > Category > Type.
3.  I am trying to figure out how to aggregate or project the data using LINQ to do a two-deep higherarchy.
4.  I tried turning off LoadOnDemand but that made the TreeView call the action method once for each record in the Product list.

I have tried inserting the TreeView Razor code directly into the _Layout view (not using a partial view).   I realize that I may need to move the action method into a base controller class and inherit it in every controller to stop it from appending the list to the parent node. If I cant get this working soon, I may have to either use Kendo UI Professional or an open source alternative.

Thank you in advance for your help!
















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Wayne
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answered on 19 Jul 2014, 07:28 PM
The solution in code:

The _Layout view:

@Html.Partial("_ProductTree")


or 

@RenderSection("productTree", false)


then in the content view

    @section productTree
    {
        @Html.Partial("_ProductTree")
    }

the _ProductTree partial view

  
@(Html.Kendo().TreeView().Name("ProductTree")
      .DataSource(d => d
          .Model(m => m
              .Id("Id")
              .HasChildren("HasChildren")
              .Children("Children"))
      .Read(r => r.Action("_ProductTree", "Home")))
      .DataTextField("Name"))


I moved the action method to a BaseController abstract class that can be inherited by any controller that needs to display the ProductTree TreeView.  The data was pulled from a ProductService and a CategoryService and aggregated using LINQ projection into anonymous objects:

[ActionName("_ProductTree")]
public JsonResult GetProductData()
{
    var products = _productBusinessService.GetProducts();
 
    foreach (var product in product)
    {
        foreach (var category in client.Categories)
        {
            category.ProductTypes =
                _productService.GetProductTypes(category.CategoryId);                                          
        }
    }
 
    var productTreeData = products.Select(p => new
    {
        Id = p.ProductId,
        Name = p.ProductName,
        HasChildren = p.Categories.Any(),
        Children = p.Categories.Select(c => new
        {
            Id = c.CategoryId,
            Name = c.CategoryName,
            HasChildren = c.ProductTypes.Any(),
            Children = c.ProductTypes.Select(t => new
            {
                Id = t.ProductTypeId,
                Name = t.ProductTypeName,
                HasChildren = false
            }).OrderBy(t => t.Name).ToList()
        }).OrderBy(c => c.Name).ToList()
    }).OrderBy(p => p.Name).ToList();
 
    return Json(productTreeData, JsonRequestBehavior.AllowGet);
}


The result is a 3-deep, fully populated, sorted Telerik UI for ASP.NET Treeview containing the names and IDs of Product >> Category >> ProductType.  Turning LoadOnDemand on or off did not seem to make a difference in this case.  It should make a difference when using Bind in a TreeView.

I hope this helps!
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