Code First Approach in MVC Using Entity Framework

Rahul Saxena
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CodeFirstApproach.zip

Here with Entity Framework we can develop an application using any of the following 3 approaches.

Code First
Model First
Database First

Now we will learn the Code First step-by-step. Open Visual Studio 2012 and go to "File" -> "New" -> "Project...".

Now right-click on the project in the Solution Explorer and select Manage NuGet Packages.

Now right-click on the Model and select Add New Class.

In your Class define a property or column name that you want in your SQL Server Table.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
namespace CodeFirstApproach.Models
{
public class Student
{
public int ID { get; set; }
public string Name { get; set; }
public string Email { get; set; }
public string Class { get; set; }
public string Address { get; set; }
public string Mobile { get; set; }
}
}

Now again right-click on the Model Folder and select Add New Class.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.Entity;
using System.ComponentModel.DataAnnotations.Schema;
namespace CodeFirstApproach.Models
{
public class StudentContext:DbContext
{
public StudentContext(): base("name=DbConnectionString")
{
}
public DbSet<Student> Students { get; set; }
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
modelBuilder.Entity<Student>().HasKey(b => b.ID);
modelBuilder.Entity<Student>().Property(b => b.ID)
.HasDatabaseGeneratedOption(DatabaseGeneratedOption.Identity);
base.OnModelCreating(modelBuilder);
}
}
}

Here I am using a connection string. Be sure you define it in your web.config file.

<add name="DbConnectionString"
connectionString="Data Source=INDIA\MSSQLServer2k8;Initial Catalog=MyCodeFirstAPPDB;User ID=sa; Password=india;"
providerName="System.Data.SqlClient" />

Now we need to add a controller then right-click on the Controller Folder and select Add -> Controller.

Here in the Student Controller define an action method for Create/Read/Update/Delete as in the following.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using CodeFirstApproach.Models;
namespace CodeFirstApproach.Controllers
{
public class StudentController : Controller
{
//
// GET: /Student/
StudentContext objContext;
public StudentController()
{
objContext = new StudentContext();
}
public ActionResult Index()
{
var students = objContext.Students.ToList();
return View(students);
}
public ViewResult Details(int id)
{
Student student = objContext.Students.Where(x => x.ID == id).SingleOrDefault();
return View(student);
}
#region Create Student
public ActionResult Create()
{
return View(new Student());
}
[HttpPost]
public ActionResult Create(Student student)
{
objContext.Students.Add(student);
objContext.SaveChanges();
return RedirectToAction("Index");
}
#endregion
#region Edit Student
public ActionResult Edit(int id)
{
Student student = objContext.Students.Where(x => x.ID == id).SingleOrDefault();
return View(student);
}
[HttpPost]
public ActionResult Edit(Student model)
{
Student student = objContext.Students.Where(x => x.ID == model.ID).SingleOrDefault();
if (student != null)
{
objContext.Entry(student).CurrentValues.SetValues(model);
objContext.SaveChanges();
return RedirectToAction("Index");
}
return View(model);
}
#endregion
#region Delete Student
public ActionResult Delete(int id)
{
Student student = objContext.Students.Find(id);
return View(student);
}
[HttpPost]
public ActionResult Delete(int id, Student Model)
{
var student = objContext.Students.Where(x => x.ID == id).SingleOrDefault();
if (student != null)
{
objContext.Students.Remove(student);
objContext.SaveChanges();
}
return RedirectToAction("Index");
}
#endregion
}
}