Getting error : Sequence contains no elements

[Craig Tarp]

hi all

I changed my model for a treeview to use an IEnumerable list of Course ( bascially am emulating the MVC treeview DEMO for model binding with treeview ) I get the error that the Sequence contains no elements

System.Web.Mvc.ViewPage<IEnumerable<XP.Models.CustomClasses.Course>>

<%

= Html.Telerik().TreeView().Name("TreeView")

 

.ClientEvents(events => events

 

.OnNodeDragStart(

"onNodeDragStart")

 

.OnNodeDragCancelled(

"onNodeDragCancelled")

 

.OnNodeDragging(

"onNodeDragging")

 

.OnNodeDrop(

"onNodeDrop")

 

.OnNodeDropped(

"onNodeDropped")

 

)

.DragAndDrop(

true)

 

.DragAndDrop(settings => settings

.DropTargets(

".drop-container")

 

)

.BindTo(Model, mappings =>
                {
                    mappings.For<XP.Models.CustomClasses.Unit>(binding => binding
                   .ItemDataBound((item, unit) =>
                                      {
                                          item.Text = unit.Title;
                                          item.Value = unit.Id.ToString();
                                          item.ImageUrl = "../../Images/unit32.png";
                                      })
                    );

                    mappings.For<XP.Models.CustomClasses.Lesson>(binding => binding
                   .ItemDataBound((item, lesson) =>
                                      {
                                          item.Text = lesson.Title;
                                          item.Value = lesson.Id.ToString();
                                          item.ImageUrl = "../../Images/lesson32.png";
                                      })
                    );

                    mappings.For<XP.Models.CustomClasses.Section>(binding => binding
                   .ItemDataBound((item, section) =>
                                   {
                                       item.Text = section.Title;
                                       item.Value = section.Id.ToString();
                                       item.ImageUrl = "../../Images/section32.png";
                                   })
               );
                }).HtmlAttributes(new { @class = "t-group" })

jQuery(

'#TreeView').tTreeView({ onLoad: onLoad, dragAndDrop: { "dropTargets": ".drop-container" }, onNodeDrop: onNodeDrop, onSelect: onSelect, onNodeDropped: onNodeDropped });

 

Prior to this I was just passing in the model (complex) and it worked fine with the exception that the textValue was not b
eing populated with the appropriated ID     (course ID  or section ID   etc)  ...Without the ID , I can't edit or Delete so I have to have the ID......All googling has let me to believe that there could be an issue with LINQ find a null mapping ....as the some lessons may not have sections..... Should I or can I specifiy where the Child of the Unit is Not NULL....would that fix this situation???   .Children(unit => unit.Lessons)  

thanks in Advance...you guys are great resource...

Craig T

BTW: error is on this line

 

System.InvalidOperationException: Sequence contains no elements
Line 182: <%= Html.Telerik().TreeView().Name("TreeView") 

[Rockey]

Hello,

That means your not getting the necessary items from the table..so child values shouldn't be null.. make sure on debug u r getting all items from table.. 

because similar problem I faced it before that time my child items are null values.. 

thanks