How to use Kendo UI Grid with ToDataSourceResult(), IQueryable, ViewModel and AutoMapper?

Question

What is the best approach to load/filter/order a Kendo grid with the following classes:

Domain:

public class Car
{
    public virtual in         


        

Answer 1

One good way to solve it if you use Telerik Data Access or any other IQueryable enabled interface/ORM over your data, is to create views directly in your database RDBMS that map one-to-one (with automapper) to your viewmodel.

1. Create the viewmodel you wish to use

   public class MyViewModelVM
   {
       public int Id { get; set; }
       public string MyFlattenedProperty { get; set; }
   }
   

2. Create a view in your SQL Server (or whatever RDBMS you're working with) with columns exactly matching the viewmodel property names, and of course build your view to query the correct tables. Make sure you include this view in your ORM classes

   CREATE VIEW MyDatabaseView
   AS
   SELECT
   t1.T1ID as Id,
   t2.T2SomeColumn as MyFlattenedProperty
   FROM MyTable1 t1
   INNER JOIN MyTable2 t2 on t2.ForeignKeyToT1 = t1.PrimaryKey
   

3. Configure AutoMapper to map your ORM view class to your viewmodel

   Mapper.CreateMap();
   

4. In your Kendo grid Read action, use the view to build your query, and project the ToDataSourceQueryResult using Automapper

   public ActionResult Read([DataSourceRequest]DataSourceRequest request)
   {
       if (ModelState.IsValid)
       {
           var dbViewQuery = context.MyDatabaseView;
   
           var result = dbViewQuery.ToDataSourceResult(request, r => Mapper.Map(r));
   
           return Json(result);
       }
   
       return Json(new List().ToDataSourceResult(request));
   }
   

It's a bit of overhead but it will help you in achieve performance on two levels when working with large datasets:

• You are using native RDBMS views which you can tune yourself. Will always outperform complex LINQ queries you build in .NET
• You can leverage the Telerik ToDataSourceResult benefits of filtering, grouping, aggregating, ...