Entity Framework Core 2.2 + Hierarchy

[Joel]

I use Entity Framework Core 2.2.  It does me a solid by constructing the entire hierarchy from the database without me asking it to.  That said, your TreeList actually binds to a Flat structure.  Your model definition then defines how the hierarchy is built.

Do you have an example of how you use EF with your TreeList?  Do you have tools or a method that I could use to convert what I get from EF over to what your control needs?

I have a self-referencing Group table:

• Id
• ParentId
• Name
• Description

ParentId references Id

@(Html.Kendo().TreeList<GsiPortal.Models.Group>()
    .Name("treelist")
    .Columns(columns =>
    {
        columns.Add().Command(c => { c.Custom().Text("Details").Name("detailButton").Click("toDetails"); }).Width(120);
        columns.Add().Field(e => e.Name).Width(220).TemplateId("icon-template");
        columns.Add().Field(e => e.Description).Width(220);
        columns.Add().Command(c => { c.Custom().Text("Create").Name("createButton").Click("toCreate"); }).Width(120);
    })
    .Selectable(selectable => selectable.Mode(TreeListSelectionMode.Single))
    .DataSource(dataSource => dataSource
        .ServerOperation(false)
        .Read(read => read.Action("IndexJson", "Groups").Data("readParams"))
        .Model(m =>
        {
            m.Id(f => f.Id);
            m.ParentId(f => f.ParentId);
            m.Expanded(true);
            m.Field(f => f.Name);
            m.Field(f => f.Description);
        }
    )
    .Events(events =>
    {
        events.Error("onError");
    })
    ))

    <script>
        var groupId = Number(@(ViewBag.GroupId));

        function readParams() {
            return { id: groupId };
        }

        function toDetails(e) {
            e.preventDefault();
            var dataItem = this.dataItem($(e.currentTarget).closest("tr"));

            if (dataItem != null) {
                window.location.href = '@Url.Action("Details", "Groups")/' + dataItem.Id;
            }
        }

        function toCreate(e) {
            e.preventDefault();
            var dataItem = this.dataItem($(e.currentTarget).closest("tr"));

            if (dataItem != null) {
                window.location.href = '@Url.Action("Create", "Groups")/?parentId=' + dataItem.Id;
            }
        }

        function onError(e) {
            alert(e.toString());
        }


    </script>

[Preslav]

Hello Joel,

At this stage, we do not have an example of how to use Entity Framework hierarchy with our TreeList. What I could suggest is to manually flatten the data. To do that, you might be interested in checking these resources:

• https://stackoverflow.com/questions/11830174/how-to-flatten-tree-via-linq
• http://blogs.interknowlogy.com/2008/10/10/use-linqs-selectmany-method-to-flatten-collections/

Generally speaking, there is no recommended way to flatten the data, you could use anything that fits your application requirements.


Regards,
Preslav
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