Hello Flavio,

Thank you for posting in our forums.

I think that a similar question of yours was answered some time ago by Angel Todorov

http://es.infragistics.com/community/forums/p/66844/337969.aspx#337969

You need to enable Load on demand (LoadOnDemand = true in the MVC wrapper, or set initialDataBindDepth to 0 in the options, if you are using just the client-side widget).

Hope this helps.

http://es.infragistics.com/products/jquery/sample/hierarchical-grid/hierarchical-grid-load-on-demand

and this little manual:

http://help.infragistics.com/Help/NetAdvantage/jQuery/2012.2/CLR4.0/html/igHierarchicalGrid_Load_on_Demand.html#loadOnDemandMVC

I am in the case of MVC controller side hierarchical grid (C# syntax).
I think I completely did all the things I found in the sample and in the manual page...so, my code is the following one:

        public ActionResult Index()
        {
            GridModel gm = new GridModel();
            _createGridModel(gm);

            return View(gm);
        }
 
        public JsonResult BindParent()
        {
            GridModel gm = new GridModel();
            _createGridModel(gm);

            ...loading parentObjectList as List<ParentObject>()

            gm.DataSource = parentObjectList .AsQueryable();
                return gm.GetData();
        }

        public JsonResult BindChild(string path, string layout)
        {
            GridModel gm = new GridModel();
            _createGridModel(gm);

            ...loading childrenObjectList as List<ChildrenObject>()

            gm.DataSource = childrenObjectList .AsQueryable();
                return gm.GetData(path, layout);
        }

        private GridModel _createGridModel(GridModel gm)
        {
            ...loading parentObjectList as List<ParentObject>()

            gm.ID = "parent_grid";
            gm.DataSource = parentObjectList .AsQueryable();
            gm.AutoGenerateColumns = false;
            gm.AutoGenerateLayouts = false;
            gm.PrimaryKey = "Id";
            gm.Width = "100%";

            #region Grid Columns
            gm.Columns.Add(new GridColumn("Id", "Id", "number", "0"));
            gm.Columns.Add(new GridColumn("Description", "Description", "string", "35%"));
            ...
            gm.RenderCheckboxes = true;
            #endregion

            #region Grid Hiding
            GridHiding hiding = new GridHiding();

            ColumnHidingSetting hSetId = new ColumnHidingSetting();
            hSetId.ColumnKey = "Id";
            hSetId.AllowHiding = false;
            hSetId.Hidden = true;
            hiding.ColumnSettings.Add(hSetId);
            ColumnHidingSetting hSetDescription = new ColumnHidingSetting();
            hSetDescription .ColumnKey = "Description";
            hSetDescription .AllowHiding = false;
            hSetDescription .Hidden = false;
            hiding.ColumnSettings.Add(hSetDescription );
            ...

            gm.Features.Add(hiding);
            #endregion

            #region HierarchicalGrid
            GridColumnLayoutModel hgml = _getHierarchicalGridColumnLayout();
            gm.ColumnLayouts.Add(hgml);
            #endregion

                gm.LoadOnDemand = true;
                gm.DataSourceUrl = Url.Action("BindParent");
                gm.ColumnLayouts[0].DataSourceUrl = Url.Action("BindChild");

            return gm;
        }

        private GridColumnLayoutModel _getHierarchicalGridColumnLayout()
        {
            GridColumnLayoutModel hierarchicalGm = new GridColumnLayoutModel();
            hierarchicalGm.ID = "hgrid";
            hierarchicalGm.AutoGenerateColumns = true;
            hierarchicalGm.AutoGenerateLayouts = false;
            hierarchicalGm.Key = "Allegati";
            hierarchicalGm.PrimaryKey = "Id";
            hierarchicalGm.ForeignKey = "DispositivoId";
            hierarchicalGm.Caption = "Allegati";
            hierarchicalGm.Width = "100%";

            return hierarchicalGm;
        }

But I still get this error:

Error: The remote request to fetch data has failed:  (error) undefined @ ...Scripts/IG/modules/infragistics.ui.grid.framework.js:25

I also tried to set data binding on js code:

     $(function () {
         $("#grid_anagrafica_tipologie_dispositivo").live("iggriddatabinding", function (evt, ui) {
             $("#grid_anagrafica_tipologie_dispositivo").igGrid("option", "dataSourceType", "json");
         });
     });

But the result is the same...
Note that parent grid has been creating right: I can see all the objects with a '+' on the left. The problem is when I try to expand a parent record into its children: I can see the subgrid rendering with all the columns, but the application stops with the loading picture thread, and I can see on the debugging console the error mentioned above...
Through the debug I can see that BindChild method is correctly reached, and the error is given here, at the end of the code:
       gm.GetData(path, layout);
returns a null object exception...


I don't know if I forgot some properties to be set, or if I did something wrong in the datasource/databinding management...

Thanks in advance!!!!

Flavio