Remote Binding not appears expand node icon

[Dario]

I'm using remote binding, but not appears arrow to expand node.

This is method

public JsonResult Read_DropDownTreeNewCustomerCategoriesData(string Code)
        {
            var result = GetHierarchicalNewCustomerCategoryData()
                .Where(x => !string.IsNullOrEmpty(Code) ? x.ParentCode == Code : x.ParentCode == null)
                .Select(item => new
                {
                    Code = item.Code,
                    Name = item.Name,
                    hasChildren = item.HasChildren
                });

            return Json(result.ToList());
        }

This is control

@(Html.Kendo().DropDownListFor(model=>model.NewCustomerCategoryCode)
                        .DataTextField("Name")
                        .DataValueField("Code")
                        .DataSource(dataSource => dataSource
                            .Read(read => read
                                .Action("Read_DropDownTreeNewCustomerCategoriesData", "ListBox")
                            )
                        )
                    )

 I attached result

[Dario]

this is the model

public class NewCustomerCategory
    {
        public string Code { get; set; }
        public string ParentCode { get; set; }
        public string Name { get; set; }

        public bool HasChildren { get; set; }

    }

this is a provider

public IList<NewCustomerCategory> GetHierarchicalNewCustomerCategoryData()
        {
            var newCustomerCategories = from rec in _context.DimensionValues
                                        where rec.DimensionCodeFK == "CAT.CLIENTE NUOVO"
                                        && rec.DimensionValueType != 4
                                        orderby rec.Code, rec.Indentation
                                        select rec;

            var result = new List<NewCustomerCategory>();

            foreach (var item in newCustomerCategories.Where(dv => dv.Indentation == 0 && dv.DimensionValueType == 3))
            {
                var newItem = new NewCustomerCategory();

                newItem.Code = item.Code;
                newItem.Name = item.Name;
                newItem.ParentCode = null;
                newItem.HasChildren = false;

                //Secondo livello
                foreach (var item2 in newCustomerCategories.Where(dv => dv.Code.StartsWith(newItem.Code.Substring(0,1).ToString()) && dv.Indentation == 1 && dv.DimensionValueType == 3))
                {
                    var newItem2 = new NewCustomerCategory();

                    newItem2.Code = item2.Code;
                    newItem2.Name = item2.Name;
                    newItem2.ParentCode = newItem.Code;
                    newItem2.HasChildren = false;

                    newItem.HasChildren = true;

                    //Terzo livello
                    foreach (var item3 in newCustomerCategories.Where(dv => dv.Code.StartsWith(newItem2.Code.Substring(0, 3).ToString()) && dv.Indentation == 2 && dv.DimensionValueType == 0))
                    {
                        var newItem3 = new NewCustomerCategory();

                        newItem3.Code = item3.Code;
                        newItem3.Name = item3.Name;
                        newItem3.ParentCode = newItem2.Code;
                        newItem3.HasChildren = false;

                        newItem2.HasChildren = true;

                        result.Add(newItem3);
                    }

                    result.Add(newItem2);
                }

                result.Add(newItem);
            }

            result = result.OrderBy(x => x.Code).ToList();

            return result;
        }

[Aleksandar]

Hi Dario,

According to the provided code snippets a DropDownList is being initialized instead of a DropDownTree:

@(Html.Kendo().DropDownListFor(model=>model.NewCustomerCategoryCode)
                        .DataTextField("Name")
                        .DataValueField("Code")
                        .DataSource(dataSource => dataSource
                            .Read(read => read
                                .Action("Read_DropDownTreeNewCustomerCategoriesData", "ListBox")
                            )
                        )
                    )

Please change the widget instance to a DropDownTree and let me know if this resolves the issue.

You can also refer to the Remote Data Binding example for further details.

Regards,
Aleksandar
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[Dario]

I changed code in this way:

<div class="form-group">
    <label asp-for="NewCustomerCategoryCode" class="control-label"></label>
    @(Html.Kendo().DropDownTreeFor(model=>model.NewCustomerCategoryCode)
            .DataTextField("Name")
            .DataValueField("Code")
            .AutoWidth(true)
            .HtmlAttributes(new { style = "width: 100%" })
            .DataSource(dataSource => dataSource
                .Read(read => read
                    .Action("Read_DropDownTreeNewCustomerCategoriesData", "ListBox")
                )
            )
        )
<span asp-validation-for="NewCustomerCategoryCode" class="text-danger"></span>
</div>

But I have same effect

[Aleksandar]

Hello Dario,

I reviewed the updated code and indeed the configuration looks correct. I tried to reproduce the issue but without success. Can you take a look at the attached sample project, modify it so the issue is replicated and send it back to me for further investigation?

Regards,
Aleksandar
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[Dario]

Hi Aleksandard,

I can't use your solution because I'm using Core 3.1

I would attached a solution that gives me the issue, it doesn't accept zip file.

[Aleksandar]

Hello Dario,

In general, you should be able to attach a zip file to a forum post. You might get an error if the file is too large, so I suggest removing any unnecessary data and trying again. If you still experience an issue you can upload it in a storage location of your choice.

The approach demonstrated in the sample would be applicable in an ASP.NET Core 3.1 app as well. I have made such an example as well. 

Regards,
Aleksandar
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[Dario]

Unfortunately, it doesn't accept zip format.

[Dario]

How can I attach zip file?

[Aleksandar]

Hi Dario,

I investigated further and indeed there was a restriction for attaching zip files to this forum. It is now removed and you should be able to attach a zip file.

Regards,
Aleksandar
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