How to pass a parameter to the Read method of signalr transport for Kendo UI grid data source - kendo-ui

Question

I was looking at the demo:
Telerik's Demo
and this
Telerik's Example
I still cannot figure out how, using this technique, to pass a parameter
to the Read method, so instead of reading ALL games or products, it reads ONLY a
subset of games or products, by category ID lest say. If I change the Read method in
the server-side code to take a parameter, it never gets hit anymore,
and I cannot figure out how to pass a parameter from the transport
client-side definition definition... Any help would be highly
appreciated!

Answer 1

I posted the question to the Telerik's forums and got this which should work!
Telerik's Answer

Answer 2

In case anyone else comes along in the future and the link in the other answer is gone, or for those who don't want to download a project file and sift through it themselves, here's more detail from the answer given on the Telerik forums:
They use Kendo.DynamicLinq to "bind the request parameters."
They created a custom class that mirrors the structure of the existing DataSourceRequest class typically used in AJAX grid actions.
using System.Collections.Generic;
using Kendo.DynamicLinq;
namespace SignalRLocalHub.Models
{
public class MyDataSourceRequest
{
public int Take { get; set; }
public int Skip { get; set; }
public int Page { get; set; }
public int PageSize { get; set; }
public Filter Filter { get; set; }
public IEnumerable<Sort> Sort { get; set; }
public IEnumerable<Aggregator> Aggregates { get; set; }
}
}
In the ProductHub (SignalR hub) class, this is the Read method:
public DataSourceResult Read(MyDataSourceRequest request)
{
return productService.Read()
.ToDataSourceResult(
request.Take,
request.Skip,
request.Sort,
request.Filter,
request.Aggregates);
}
The productService.Read method it calls, for reference, looks like this:
//int take, int skip, IEnumerable<Sort> sort, Filter filter, IEnumerable<Aggregator> aggregates
public IQueryable<ProductViewModel> Read()
{
return entities.Products
.OrderBy(p => p.ProductID)
.Select(product => new ProductViewModel
{
ProductID = product.ProductID,
ProductName = product.ProductName,
UnitPrice = product.UnitPrice.HasValue ? product.UnitPrice.Value : default(decimal),
UnitsInStock = product.UnitsInStock.HasValue ? product.UnitsInStock.Value : default(short),
Discontinued = product.Discontinued
});
}
And finally, here is the grid's DataSource configuration:
.DataSource(d => d
.SignalR()
.AutoSync(true)
.Transport(tr => tr
.Promise("hubStart")
.Hub("hub")
.Client(c => c.Read("read").Create("create").Update("update").Destroy("destroy"))
.Server(s => s.Read("read").Create("create").Update("update").Destroy("destroy"))
)
.ServerFiltering(true)
.Filter(f => f.Add(m => m.UnitPrice).IsEqualTo(10))
.ServerPaging(true)
.PageSize(10)
.Schema(s => s
.Data("Data")
.Total("Total")
.Aggregates("Aggregates")
.Model(m =>
{
m.Id(e => e.ProductID);
m.Field(e => e.ProductID).Editable(false);
})
)
)
This allows sorting, paging, and filtering by any field that is part of the grid view model. So as long as your "category ID" is a property of the grid view model and the grid is configured to be able to filter by that field, this method should work.