No generic method 'Sum' on type 'System.Linq.Enumerable' is compatible

[Mitchell]

I am having some issues with the MVC Wrappers for Kendo UI. It seems that IEnumerable does not support any aggregate values other than count. The exception that I get is: No generic method 'Sum' on type 'System.Linq.Enumerable' is compatible with the supplied type arguments and arguments. No type arguments should be provided if the method is non-generic.  I am using System.LInq.Dynamic but this issue occurs without using a Dynamic query.

I am not sure how to get around this issues nor am I sure if it is a flaw with Kendo.
Controller

public ActionResult Index() { return View(); }
public ActionResult Read([DataSourceRequest] DataSourceRequest request) { return GetView(request); }
private IEnumerable<dynamic> GetData() { var db = new NwEntities(); return db.Products.Select("new(ProductID,ProductName,UnitPrice)"); }
private JsonResult GetView(DataSourceRequest request) { return Json(GetData().ToDataSourceResult(request)); }

View

@model IEnumerable<dynamic>
@(
 Html.Kendo().Grid(Model).Name("Grid")
    .DataSource(ds =>
        ds.Ajax()
        .Model(m =>
        {
            m.Id("ProductID");
            m.Field("ProductName", typeof(string));
            m.Field("UnitPrice", typeof(decimal));
        })
        .Aggregates(aggregate => aggregate.Add(a => "UnitPrice").Count().Sum())
        .Read(r => r.Action("Read", "Home"))
    )
    .Columns(columns =>
    {
        columns.Bound("ProductID");
        columns.Bound("ProductName");
        columns.Bound("UnitPrice").Format("{0:c}");
    })
    .Groupable()
)

I have spent a week trying to get this to work with no luck and this is a critical issue.

[Mitchell]

The same thing seems to happen to DataTables as well.  This is a critical issue that I need resolved.

[Daniel]

Hello Mitchell,

You should use the overload that accepts the member name and member type when binding to dynamic objects e.g.

Aggregates(agg => agg.Add("UnitPrice", typeof(decimal)).Sum().Count())

Kind regards,
Daniel
the Telerik team

[Priyank]

Hello Admin,

I am getting error when i applied sum() aggregates with group by.

I am using kendo ui for MVC. I am binding the grid using ServerOperation(true). We have some group by functionality with aggregates function in dynamic way. So we have create jquery function and add group by and aggregates with jquery.

The group by is applied on grid but aggregates sum() function is not applied on grid and throw below error

"System.InvalidOperationException: No generic method 'Sum' on type 'System.Linq.Enumerable' is compatible with the supplied type arguments and arguments. No type arguments should be provided if the method is non-generic".

I attached image of jquery code and grid code.

Update me on this.

 

Thanks.

[Tsvetomir]

Hi Priyank,

Based on the provided information, I suspect that the data type for the field is not a primitive data type. Is that correct?

The Kendo UI DataSource internally uses the Sum() LINQ query that applies the aggregate only to primitive data types. Hence, if you have a complex object such as an IEnumerable, you should handle the aggregation on your own. A similar approach where the custom aggregation is shown can be found in the live demo below:

https://demos.telerik.com/aspnet-mvc/grid/customajaxbinding

I hope you find this helpful.

 

Regards,
Tsvetomir
Progress Telerik