Grid updates using nested / child objects

[Aaron]

I have an older copy of the .net kendo ui sample code.  In the sample, the following ViewModel is included.

    public class ProductViewModel
    {
        public ProductDTO ProductMeta { get; set; }
        public int ProductID { get; set; }
        public string ProductName { get; set; }
        public decimal UnitPrice { get; set; }
        public int UnitsInStock { get; set; }
        public bool Discontinued { get; set; }
        public DateTime LastSupply { get; set; }
        public int UnitsOnOrder { get; set; }
    }

The VM also uses this class.

    public class ProductDTO
    {
        public int ProductID { get; set; }
        public string ProductName { get; set; }
        public decimal? UnitPrice { get; set; }
    }

In the Areas/razor/views/grid/editing.cshtml file, if I change the following line

@(Html.Kendo().Grid<Kendo.Mvc.Examples.Models.ProductViewModel>()
    .Name("Grid")
    .Columns(columns =>
    {
        columns.Bound(p => p.ProductName);
      columns.Bound(p => p.UnitPrice).Width(140);        

TO....

@(Html.Kendo().Grid<Kendo.Mvc.Examples.Models.ProductViewModel>()
    .Name("Grid")
    .Columns(columns =>
    {
        columns.Bound(p => p.ProductName);
      columns.Bound(p => p.ProductMeta.UnitPrice).Width(140);


The binding works correctly on update.  So if I change the value of unit price to 25, the vm.ProductMeta.UnitPrice value will be set appropriately to 25.

However, if I add the following statement (statement bolded), the binding no longer works

    .DataSource(dataSource => dataSource
        .Ajax()
        .Batch(true)
        .ServerOperation(false)
        .Events(events => events.Error("error_handler"))
        .Model(model =>
            {
                model.Id(p => p.ProductID);
              model.Field(p => p.ProductMeta.UnitPrice).DefaultValue(30);
            })

Inspecting the payload sent to the GridController.EditingUpdate() method, I notice that the value for ProductMeta.UnitPrice is not changed.

Is there a work around for this?  

It seems like the grid is not overly fond of working with nested objects exposed from VMs, especially when using the Model() method.

I'd rather not have to flatten my VM in order to get this to work.

Thanks!

[Victor]

Interesting, we are also trying to work with nested properties similair to yours. Did you resolve this issue and if so, would you share how?

/Victor

[Aaron]

Final word was that it is not supported, so we have to flatten our VM's, unfortunately.  HUGE design flaw, in my opinion.  Having to write bloated software in order to work with a third party's tooling is a HUGE no-no.  We almost ditched the grid because of this.  We would have too, if we weren't under such strict timelines.  As you know, grids come with a significant learning curve, especially when you need to do anything outside of a demo ....

[Vladimir Iliev]

Hi Aaron,

 
Please note that you can set the default value of nested property in the following way:

.DataSource(dataSource => dataSource
    .Ajax()
        .Model(model => {
            model.Id(p => p.ProductID);
            model.Field(m => m.ProductID).Editable(false);
            //define the default value of nested property by creating bew instance of parent model
            model.Field(p => p.ProductMeta).DefaultValue(new ProductMetaViewModel() { UnitPrice = 25 });

Regards,
Vladimir Iliev
Telerik

[Victor]

Hi again,

We ended up using the DefaultValue which works, but nested viewmodels certainly needs more work than normal ones.

/Victor

[Pauline]

Hi Aaron,

You might also try inspecting the request headers and creating a custom model binding for your data.
References:
http://msdn.microsoft.com/en-us/magazine/hh781022.aspx
http://blog.thekfactor.info/posts/tag/imodelbinder/

Worked for me.