Supply on demand data to a Telerik UI ASP.NET Core Grid component using code generated by AspCoreGen3Razor

Technologies Used: Kendo UI, Grid, Telerik UI, AspCoreGen3MVC, AspCoreGen3Razor, ASP.NET, C#

The generated back end code (middle tier, data tier, web api, stored procedures, etc) for either AspCoreGen3Razor or AspCoreGen3MVC can be reused in any project that needs data from a Microsoft SQL Server database. You can reuse the generated back end code in a web, mobile, desktop, or even web api projects. You can easily fill UI components with as little as one line of code using the generated code as a datasource.

Telerik UI/Kendo UI is among the most popular components used by developers worldwide. This tutorial will show how to use the generated back end code for AspCoreGen3Razor as a datasource for a Telerik UI ASP.NET Core Grid component. The Telerik UI ASP.NET Core Grid component will be able to dynamically get data on demand using paging and sorting by column.

Note: The code reuse also applies, but not limited to: Telerik UI for Blazor, ASP.NET MVC, ASP.NET Ajax, Kendo UI for JQuery, Angular, Vue, KendoReact, and many more.

You need the following for this tutorial:
  • Microsoft Northwind Database (please Google it)
  • Microsoft SQL Server 2003 and above
  • You will need a User with an Admin username/password or with enough rights in the MS SQL Server (or Azure SQL). A blank username/password will not work.
  • Visual Studio 2019 (the generated code will not work in Visual Studio 2017 and below)
  • AspCoreGen 3.0 Razor Professional Plus or AspCoreGen 3.0 MVC Professional Plus (optional)
  • AspCoreGen 3.0 Razor Ad-Hoc SQL Sample Project
  • Telerik UI ASP.NET Core Demo Application

Here's a snapshot of what we're trying to do:

Paging.cshtml View

Note: You need to have the Microsoft Northwind Database installed in a Microsoft SQL Server for this tutorial. Download and installation of this database is beyond the scope of this tutorial. We will be using the Products table to retrieve rows of data from this database.

Northwind Database

1. Download the #5. Ad-Hoc SQL Sample Project here: You will see the project towards the bottom of the page. Click the Download Sample Code link. This web application project was generated by AspCoreGen3Razor, the solution contains 2 projects, a Web Application and a reusable Class Library project. We only need the Class Library project which consist of the Business Object and Data Tier class files and we can discard the web application project.

FYI: You can download and use any of the six (6) projects from AspCoreGen3Razor's Web Generated Project Examples or AspCoreGen3MVC's Web Generated Project Examples. Or generate your own code using AspCoreGen3Razor or AspCoreGen3Razor. Any of these will work, just follow along with the tutorial.

2. Download the Telerik UI ASP.NET Core Demo Application. This will be installed in your computer and can be opened in Visual Studio 2019.

FYI: You can use the Grid component for any Telerik UI/Kendo UI products listed above, they will work just fine. If you already bought a Telerik UI/Kendo UI product, then the demo application should already be installed in your computer/system, in this case just follow along (no need to download).

3. Open the Kendo.Mvc.Examples.sln solution (in Visual Studio 2019) that was installed in your computer. In my case, the solution file can be found in C:\Program Files (x86)\Progress\Telerik UI for ASP.NET Core R3 2020\wrappers\aspnetcore\Examples\AspNet.Core\VS2019\Kendo.Mvc.Examples directory.


Solution in Visual Studio

4. Copy the Class Library Project (NwndAdHcAPI) that we downloaded in #1 to the C:\Program Files (x86)\Progress\Telerik UI for ASP.NET Core R3 2020\wrappers\aspnetcore\Examples\AspNet.Core\VS2019\ folder, the same folder where the Kendo.Mvc.Examples project is located, as shown below.
Copy NwndAdHcAPI Class Library Project

5. Back in Visual Studio, add the NwndAdHcAPI.csproj to the Kendo.Mvc.Examples solution by adding an existing project as shown below.

Add Existing Project

Add Existing Project

6. You should now have 2 projects showing in the Visual Studio Solution Explorer.

2 Projects in Solution

7. Open the AppSettings.cs class under the NwndAdHcAPI project and update the DatabaseUserName and DatabasePassword for the Northwind Database that you're using.

Generated ASP.NET Core 3.1 Razor Page Web Application

8. Add the NwndAdHcAPI project as a Project Reference to the Kendo.Mvc.Examples project.

Project Reference

Project Reference

9. Instead of creating a new MVC view, we will update/edit an existing one. Open the Paging.cshtml view in the Kendo.Mvc.Examples project, under the Views/Grid folder. Delete all the code in it and replace with the code shown below:


10. Now open the related PagingController.cs controller under the Controllers/Grid folder. Update the code to what you see below:


Code in the GetProducts action method shown above will return only the amount of data the Telerik UI Grid component is asking for. The code that we deleted (Telerik example code) returns all data from the database while the code we have above returns data on-demand.

The GetProducts action method is called whenever an event is triggered on the Telerik UI Grid component found in the Paging.cshtml view. When the Sort or the Paging event is triggered, the Grid passes a DataSourceRequest to the GetProducts action method.

As shown below, with the DataSourceRequest, we can figure out:

- How many rows (Page Size) to get from the database
- Where to start taking data from the database (Skip, Take)
- The Column/Field to Sort and the Sort Direction (Ascending or Descending)

Rows, Skip, Take, Sort Order

We can then retrieve just the right amount of data on-demand after getting these parameters.

Get data on demand

The Telerik UI Grid component expects the Total Number of Records for the specific Datasource it's using, for our example, it's grabbing data from the Northwind database's Products table. We need to return the Total Number of Records from the Products table so that the Telerik UI Grid component will be able to know the number of Pages to show.

Total Number of Records

The Telerik UI Grid component expects a JSON-formatted data that would contain parameters such as:

- Total (Total Number of Records)
- AggregateResults (for Grouping)
- Data

JSON Formatted Data

11. Run the project by pressing F5 in Visual Studio. Go to the paging link under the Functionality group.

Paging.cshtml View

Click around to see the functionality of the Telerik UI Grid component with data supplied by the AspCoreGen3Razor Generated Code.

And we're done.

As always, the code and the article are provided "As Is", there is absolutely no warranties. Use at your own risk.

Happy Coding!!!

Date Created: Thursday, January 21, 2021