Microsoft 9GD00001 manual Creating a Repository, 265

Chapter 9: Creating Web Applications with ASP.NET MVC 265

Creating a Repository

A common pattern for working with data is to build a repository that is responsible for all data-related operations. This is another way to promote separation of concerns so that you isolate logic into specific parts of an application, resulting in easier code to work with.

A repository is a class that performs create, read, update, and delete (CRUD) operations on a specific data type. Listing 9-6 shows a repository for working with customer objects. You can create this class by right-clicking the Models folder and selecting Add Class, and name the class CustomerRepository. The code also assumes that you’ve created a LINQ to SQL *.dbml, named MyShop, with a Customer entity for the Customers table in MyShop, which is the database created in Chapter 7.

Listing 9-6 A repository for working with customer data

C#:

using System;

using System.Collections.Generic; using System.Linq;

using System.Web;

namespace MyShopCS.Models

{

public class CustomerRepository

{

private MyShopDataContext m_ctx = new MyShopDataContext();

public int InsertCustomer(Customer cust)

{

m_ctx.Customers.InsertOnSubmit(cust); m_ctx.SubmitChanges();

return cust.CustomerID;

}

public void UpdateCustomer(Customer cust)

{

var currentCust =

(from currCust in m_ctx.Customers

where currCust.CustomerID == cust.CustomerID select currCust)

.SingleOrDefault(); if (currentCust != null)