Build the Team Efficiency Dashboard Project

Step 7: Telerik UI Datasource

In this chapter you'll learn how to work with Telerik UI datasources.

Working with the Telerik UI Datasource

Overview

The Kendo UI DataSource component plays a central role in practically all web applications built with Kendo UI. It is an abstraction for using local data arrays of JavaScript objects or remote data web services returning JSON, JSONP, OData or XML.

The Kendo UI DataSource has many abilities and responsibilities, among which to:

• Retrieve data from a remote endpoint.
• Maintain the structure and type of the data (schema).
• Process serialization formats to and from a remote endpoint.
• Synchronize updates, create, update, delete to and from a remote endpoint.
• Maintain an in-memory cache of data, including changes for updating to a remote endpoint.
• Calculate and maintain aggregates, sorting order and paging.
• Provide a query mechanism via filter expressions.

For detailed information on the capabilities of the DataSource, refer to its configuration API methods, and events, and demos.

At this point the dashboard is showing all invoice data. Let's use the EmployeeList list view and StatsFrom/StatsTo date pickers to filter the invoice grid by invoking the grid's datasource.

Exercise: Create a Filter

1. In the /Views/Home/Index.cshtml view, find the scripts section.

   Razor

    <script>
    	...
    </script>

2. Add a function named getEmployeeFilter that gets the employeeId, salesPerson, statsFrom and statsTo values and returns a JSON object.

   The resulting code should be like the one shown in the example below.

   Razor

    function getEmployeeFilter() {
        var employee = getSelectedEmployee(),
            statsFrom = $("#StatsFrom").data("kendoDatePicker"),
            statsTo = $("#StatsTo").data("kendoDatePicker");
   
        var filter = {
            employeeId: employee.EmployeeId,
            salesPerson: employee.FullName,
            statsFrom: statsFrom.value(),
            statsTo: statsTo.value()
        }
        return filter;
    }

3. In the /Views/Invoice/Index.cshtml view, find the EmployeeSales grid.

   Razor

    @(Html.Kendo().Grid<KendoQsBoilerplate.Invoice>()
          .Name("EmployeeSales")
    	  ...
          .Scrollable(scrollable => scrollable.Enabled(false))
          .DataSource(dataSource => dataSource
              .Ajax()
              .Read(read => read.Action("Invoices_Read", "Invoice"))
          )
    )

4. On the grid's DataSource property, set the Data property to getEmployeeFilter. The Data property supplies additional data to the server. In this case the data is our filter parameters.

   Razor

    .DataSource(dataSource => dataSource
                .Ajax()
                .Read(read => read.Action("Invoices_Read", "Invoice")
                .Data("getEmployeeFilter"))
    )

5. Add the property AutoBind to the end of the property chain and set the value to false. Setting AutoBind to false tells the Telerik UI for MVC that the datasource's Read action is invoked manually on the client.

   The resulting code should be like the one shown in the example below.

   Razor

    @(Html.Kendo().Grid<KendoQsBoilerplate.Invoice>()
          .Name("EmployeeSales")
          ...
          .Scrollable(scrollable => scrollable.Enabled(false))
          .DataSource(dataSource => dataSource
              .Ajax()
              .Read(read => read.Action("Invoices_Read", "Invoice")
              .Data("getEmployeeFilter"))
          )
    	  .AutoBind(false)
    )

6. In the /Views/Home/Index.cshtml view, add a function named refreshGrid. This function will invoke the grid's Read action.

   Razor

    function refreshGrid() {
        var employeeSales = $("#EmployeeSales").data("kendoGrid");
        employeeSales.dataSource.read();
    }

7. Find the onCriteriaChange function and add a call to the refreshGrid function. This will cause the Grid's data to refresh whenever the employee selection changes.

   Razor

    function onCriteriaChange() {
        updateEmployeeAvatar();
        refreshGrid();
    }

   Next, we'll need to update the grid's Read action to apply the filter using Entity Framework.

8. Open Controllers/InvoiceController.cs and find the Invoices_Read action.

   Razor

    public ActionResult Invoices_Read([DataSourceRequest]DataSourceRequest request)
    {
        IQueryable<Invoice> invoices = db.Invoices;
        DataSourceResult result = invoices.ToDataSourceResult(request, invoice => new {
            OrderID = invoice.OrderID,
            CustomerName = invoice.CustomerName,
            OrderDate = invoice.OrderDate,
            ProductName = invoice.ProductName,
            UnitPrice = invoice.UnitPrice,
            Quantity = invoice.Quantity,
            Salesperson = invoice.Salesperson
        });
   
        return Json(result);
    }

9. Add the salesPerson, statsFrom and statsTo parameters to the action. Note that the additional parameters match the parameters returned by the getEmployeeFilter function exactly.

   Razor

    public ActionResult Invoices_Read([DataSourceRequest]DataSourceRequest request,
        string salesPerson,
        DateTime statsFrom,
        DateTime statsTo)

10. Using the parameter values, filter the invoices using a Where LINQ query.

    The resulting code should be like the one shown in the example below.

    Razor

     public ActionResult Invoices_Read([DataSourceRequest]DataSourceRequest request,
         string salesPerson,
         DateTime statsFrom,
         DateTime statsTo)
     {
         var invoices = db.Invoices.Where(inv => inv.Salesperson == salesPerson)
             .Where(inv => inv.OrderDate >= statsFrom && inv.OrderDate <= statsTo);
         DataSourceResult result = invoices.ToDataSourceResult(request, invoice => new {
             OrderID = invoice.OrderID,
             CustomerName = invoice.CustomerName,
             OrderDate = invoice.OrderDate,
             ProductName = invoice.ProductName,
             UnitPrice = invoice.UnitPrice,
             Quantity = invoice.Quantity,
             Salesperson = invoice.Salesperson
         });
    
         return Json(result);
     }

11. Run the project to see the behavior. Now the EmployeeList and EmployeeSales grid are in sync. When an employee is selected, only that employee's data will show in the grid.

    

At this point, the EmployeeList is acting as a filter for the EmployeeSales. However, the data shown does not reflect the StatsFrom/StatsTo date range. With the filtering code in place, additional controls are wired up with relative ease. Let's wire up the StatsFrom/StatsTo DatePickers to EmployeeSales.

Exercise: Trigger the Grid DataSource from a DatePicker Event

1. In the /Views/Home/Index.cshtml view, find the StatsFrom DatePicker.

   Razor

    @(Html.Kendo().DatePicker()
        .Name("StatsFrom")
        .Value(new DateTime(1996, 1, 1))
    )

2. Add the Events property and set the Change event to onCriteriaChange.

   Razor

    @(Html.Kendo().DatePicker()
        .Name("StatsFrom")
        .Value(new DateTime(1996, 1, 1))
        .Events(e => e.Change("onCriteriaChange"))
    )

3. Find the StatsTo DatePicker, set the Events property, and set the Change event to onCriteriaChange.

   Razor

    @(Html.Kendo().DatePicker()
    	.Name("StatsTo")
    	.Value(new DateTime(1998, 8, 1))
    	.Events(e => e.Change("onCriteriaChange"))
    )

4. Save the changes and refresh the browser. StatsFrom/StatsTo and EmployeeList will update EmployeeSales with data based on the selected dates and employee.

   

Your Team Efficiency Dashboard is now interactive. Users can filter data using dates and employees. Next, you'll enhance the application by adding some data visualizations.