Using Entity Framework in Web API Part-2

Introduction

In Part 1 of this "Using Entity Framework in Web API " series of articles we explained how to create a application and add the Model class. Now in this article we will explain how to add the Web API Controller with the Entity Framework.

Step 1

Use the following procedure to create the Controller:

In the Solution Explorer.
Right-click on the Controller Folder.
Select "Add" -> "Controller".
Select Template "API Controller with read/write actions, using Entity Framework".
Select "Model class" from the drop down list:
Now select "DataContext" by clicking on the new data context.
Now see the Solution Explorer.

Step 2

Now perform some changes in the Context file "ItemsContext".

using System.Data.Entity;
namespace EntityAPI.Models
{
public class ItemsContext : DbContext
{
// You can add custom code to this file. Changes will not be overwritten.
//
// If you want Entity Framework to drop and regenerate your database
// automatically whenever you change your model schema, add the following
// code to the Application_Start method in your Global.asax file.
// Note: this will destroy and re-create your database with every model change.
//
// System.Data.Entity.Database.SetInitializer(new System.Data.Entity.DropCreateDatabaseIfModelChanges<EntityAPI.Models.ItemsContext>());
public ItemsContext() : base("name=ItemsContext")
{
}
public DbSet<Novel> Novels { get; set; }
public DbSet<Item> Items { get; set; }
public DbSet<ItemDetail> ItemDetails { get; set; }
}
}

Step 3

Now add a database initializer to the Model class.

In the "Solution Explorer".
Right-click on the "Model Folder".
Select "Class".
Click on the "OK" button.

Add the following code:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Entity;
namespace EntityAPI.Models
{
public class ItemsContextInitializer : DropCreateDatabaseIfModelChanges<ItemsContext>
{
protected override void Seed(ItemsContext context)
{
var novels = new List<Novel>()
{
new Novel() { Name = "Revolution 2020", DealPrice = 140, SellingPrice = 145 },
new Novel() { Name = "A Calender too Crowded", DealPrice = 295, SellingPrice = 300 },
new Novel() { Name = "How That yor are rich", DealPrice = 100, SellingPrice = 110 }
};
novels.ForEach(p => context.Novels.Add(p));
context.SaveChanges();
var item = new Item() { Customer = "Smith" };
var od = new List<ItemDetail>()
{
new ItemDetail() { Novel = novels[0], Quantity = 2, Item = item},
new ItemDetail() { Novel = novels[1], Quantity = 4, Item= item }
};
context.Items.Add(item);
od.ForEach(o => context.ItemDetails.Add(o));
context.SaveChanges();
}
}
}