Binding Non-persistent Property

[Rubens]

Hi,

Im developing an application using ASP.MVC, Kendo and OpenAccess.

After created a custom property for an specific entity, I'm trying unsuccessfully to bind it to my Datasource and Grid.

Partial Class

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ErpMvc.OpenAccess
{
    public partial class Customer
    {
        public string CustomProperty
        {
            get
            {
                return "My Custom Property Text";
            }
        }
    }
}

Service

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using ErpMvc.OpenAccess;
using Kendo.Mvc.Extensions;
using Kendo.Mvc.UI;

namespace ErpMvc.Services
{
    public class CustomerService
    {
        public static IEnumerable<Customer> GetCustomers()
        {
            var dbContext = new EntitiesModel();

            return dbContext.Customers.Select(customer => new Customer
            {
                CustomerID = customer.CustomerID,
                FirstName = customer.FirstName,
                CustomProperty = customer.CustomProperty
            });

        }
    }
}

View

@model IEnumerable<ErpMvc.OpenAccess.Customer>

@{
    ViewBag.Title = "Index";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

@(Html.Kendo().Grid(Model)
    .Name("Customers")
    .Columns(columns =>
    {
        columns.Bound(c => c.FirstName).Title("First Name");
        columns.Bound(c => c.CustomProperty).Title("Custom Property");
    })
    .Pageable()
    .Sortable()
    .Editable(editable => editable.Mode(GridEditMode.InLine))
    .DataSource(dataSource => dataSource
        .Ajax()
        .Model(model => model.Id(customerID => customerID.CustomerID))
        .Read(read => read.Action("Customers_Read", "Customer"))
        .Update(update => update.Action("Customers_Update", "Customer"))
        .PageSize(50)
     )
)

Controller

public ActionResult Customers_Read([DataSourceRequest] DataSourceRequest request)
{
    return Json(CustomerService.GetCustomers().ToDataSourceResult(request));
}

Error messages I'm getting from VS

• Property or indexer 'CustomProperty' cannot be assigned to -- it is read only

After defined a "set{}" on my CustomProperty, this error messages was resolved but I started get this other one

• (...) If 'CustomProperty' is a property please add the FieldAlias or Storage attribute to it or declare it as a field's alias.

[Doroteya]

Hello Rubens,

From Data Access' perspective, in the LINQ queries, you cannot use a non-persistent property (a property, which is not mapped to column in the database). To implement the scenario on your side, you can add a DTO class in your MVC application, which will be used to hold the query result. The DTO can have all the persistent properties you need, and the non-persistent property as well. The query also has to be changed a little bit, in order to consume the DTO. Finally the grid has to be configured to display objects of the DTO type. For example:

The DTO class

public class CustomerDTO
{
    public int CustomerID { get; set; }
    public string FirstName { get; set; }
    public string CustomProperty
    {
        get
        {
            return "My Custom Property Text";
        }
    }
}

The query:

public static IEnumerable<CustomerDTO> GetCustomers()
{
    var dbContext = new EntitiesModel();

    return dbContext.Customers.Select(customer => new CustomerDTO
    {
        CustomerID = customer.CustomerID,
        FirstName = customer.FirstName,
    }).ToList();
}

The binding of the grid in the view is demonstrated in this documentation article.

I hope this helps. If you have additional questions, do not hesitate to get back to us.


Regards,
Doroteya
Telerik

 

 

[Rubens]

Dear Doroteya,

I really appreciate 

[Rubens]

Dear Doroteya,

I really appreciate your help, perhaps I was not clear... but all that I want is nothing else than create a custom computed property to display on my grid that is an extension from a class. Something like "FullName" witch returns a combination of First and Last name.

I wouldn't like to do that directly on my View... would be much better if I could make get this value by MyClass.CustomProperty

I'm still a beginner... btw, should I really use a Data Transfer Object class for this purpose?

Thank you ;) 

[Doroteya]

Hi Rubens,

You can achieve such an outcome by simply adding a field and for the property and a set clause in it in your initial code. This will prevent the error from appearing again.

I hope this helps. If you need further information, do not hesitate to get back to us.


Regards,
Doroteya
Telerik