How to consume ItemService of Sitecore Services Client - asp.net

Question

There are few tabs and a content panel. End user (EU) will click on a tab and the panel's content changes asynchronously.
eg:
<ul class="products">
<li class="p1">product1</li>
<l1>product2</li>
</ul>
<div class="product-data">
NAME : <span> <product name here> </span>
COLOR : <span> <product color here> </span>
</div>
<script>
(function ($) {
$(".p1").click(function(){
HelloWorld();
});
function HelloWorld() {
$.ajax({
type: "POST",
url: 'http://mysite/Services/myService.asmx/HelloWorld',
data: "pid:" + someId,
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (response) {
alert(response.d);
},
failure: function (response) {
alert("ERR-" + response.d);
}
});
}
})(jQuery);
</script>
Each product is an item in the content tree. When EU clicks on a tab, an ajax call is made, which will get that product's data and bind to the panel.
I'm trying to achieve this functionality using a web service and return JSON to front end:
[WebMethod]
public string HelloWorld(string pid)
{
//get a certain product details and return it as JSON
Sitecore.Data.Items.Item newItem = Sitecore.Context.Item;
if (newItem != null)
return newItem.Name;
else
return "it was null";
}
Of course, the result is "it was null" as I understand this has to be done with Item Service of SSC, but unable to find any suitable/beginner example.
Using sitecore 8 with ASP.NET

Answer 1

You will want to use Entity Service instead of Item Service of Sitecore.Services.Client. It will let you serve custom models that are specific to the type of data you want to display for each product.
First, you will need to create a class to represent your Product. It needs to implement Sitecore.Services.Core.Model.EntityIdentity.
Just an FYI if you are using Sitecore SPEAK ensure you define a property named itemId with that casing, SPEAK requires it.
public class ProductModel : Sitecore.Services.Core.Model.EntityIdentity
{
public string itemId { get; set; }
public string ProductName { get; set; }
...
}
When Developing with Sitecore.Services.Client you'll want to follow Sitecore best practices. A simple Controller passing off all the computation to a Repository for the type of Model. In this case a ProductRepository.
The controller needs to implement EntityService with the type of Model.
[ValidateAntiForgeryToken]
[ServicesController]
public class ProductController : EntityService<ProductModel>
{
public ProductController(IRepository<ProductModel> repository)
: base(repository)
{
}
public ProductController()
: this(new SitecoreItemRepository())
{
}
}
This controller exposes the methods of the Repository Get, GetById, Add, etc.
public class ProductRepository : Sitecore.Services.Core.IRepository<ProductModel>
{
public ProductModel FindById(string id)
{
// code to find by id
}
}
See here for a full example of Entity Service and here