Asp.Net Mvc Creating Dbcontext And Entities Complete Guide

Step 1: Create a New ASP.NET MVC Project

1. Open Visual Studio.
2. Select File > New > Project...
3. Choose ASP.NET Web Application (.NET Framework) under the Web category.
4. Enter a name for your project, e.g., MvcAppWithEf, and click OK.
5. In the next window, select MVC template from the list of options and ensure Authentication is set to No Authentication or any other authentication method you prefer. Click Create.

Step 2: Install Entity Framework

Entity Framework (EF) can be added via NuGet Package Manager.

1. In Solution Explorer, right-click on the project (e.g., MvcAppWithEf) and select Manage NuGet Packages....
2. In the NuGet Package Manager, go to the Browse tab and search for EntityFramework.
3. Select the package by Microsoft and click Install. Agree to any terms and prompts that are shown.

Step 3: Create a Model Class

You will create an entity class to represent the data model. Let's create a simple Employee class.

1. Right-click on the Models folder in Solution Explorer (create it if it doesn't exist).
2. Add > New Item....
3. Choose Class and name it Employee.cs.
4. Add the following code to the Employee.cs file:

using System.ComponentModel.DataAnnotations;

namespace MvcAppWithEf.Models
{
    public class Employee
    {
        [Key]
        public int Id { get; set; }

        [Required]
        [StringLength(50)]
        public string FirstName { get; set; }

        [Required]
        [StringLength(50)]
        public string LastName { get; set; }

        public string Email { get; set; }

        public int Age { get; set; }

        public decimal Salary { get; set; }
    }
}

Step 4: Create ApplicationDbContext Class

This class will serve as a context to the database operations.

1. Right-click on the Models folder in Solution Explorer.
2. Add > New Item....
3. Choose Class and name it ApplicationDbContext.cs.
4. Add the following code to the ApplicationDbContext.cs file:

using System.Data.Entity;

namespace MvcAppWithEf.Models
{
    public class ApplicationDbContext : DbContext
    {
        public ApplicationDbContext() : base("DefaultConnection")
        {
        }

        public virtual DbSet<Employee> Employees { get; set; }
    }
}

Step 5: Configure Connection String in Web.config

You need to specify the connection string for the application to connect to your database.

1. Open the Web.config file located at the root of your project.
2. Find the <connectionStrings> section and add the following connection string:

<connectionStrings>
    <add name="DefaultConnection"
         connectionString="Data Source=(LocalDb)\MSSQLLocalDB;Initial Catalog=MvcAppWithEf;Integrated Security=True;"
         providerName="System.Data.SqlClient" />
</connectionStrings>

Step 6: Enable Migrations

1. Open the Package Manager Console (Tools > NuGet Package Manager > Package Manager Console).
2. Execute the following command to enable migrations:

Enable-Migrations

Entity Framework will create a Migrations folder in your project with Configuration.cs inside it.

Step 7: Create the Initial Migration

1. In the Package Manager Console, execute the next command to create the initial migration:

Add-Migration InitialCreate

Entity Framework generates a new migration class in the Migrations folder, which includes the SQL commands to create the database tables.

Step 8: Update Database

1. To apply the migrations to the database, run the following command in the Package Manager Console:

Update-Database

This command will generate and apply the SQL to the specified database, creating the necessary tables.

Step 9: Create Controller and Views

1. In Solution Explorer, right-click on the Controllers folder and select Add > Controller....
2. Choose MVC 5 Controller with views, using Entity Framework.
3. Name the controller EmployeesController.
4. Set the Model class to Employee and choose ApplicationDbContext as the data context class.
5. Click Add.

Visual Studio will generate a complete controller with CRUD actions and corresponding views for Employee.

Step 10: Display Employees on Home Page

To show a list of employees on the home page of the application:

1. Open the HomeController class in the Controllers folder.
2. Modify the Index action method to fetch employees:

public ActionResult Index()
{
    using (var context = new ApplicationDbContext())
    {
        return View(context.Employees.ToList());
    }
}

3. Open the Index.cshtml view in the Views/Home folder and modify it to display the list of employees:

@{
    ViewBag.Title = "Home Page";
}

@section featured {
    <section class="featured">
        <div class="content-wrapper">
            <hgroup class="title">
                <h1>@ViewBag.Title.</h1>
                <h2>Our Employees</h2>
            </hgroup>
            <table>
                <thead>
                    <tr>
                        <th>ID</th>
                        <th>Name</th>
                        <th>Email</th>
                        <th>Age</th>
                        <th>Salary</th>
                    </tr>
                </thead>
                <tbody>
                    @foreach (var employee in Model)
                    {
                        <tr>
                            <td>@employee.Id</td>
                            <td>@employee.FirstName @employee.LastName</td>
                            <td>@employee.Email</td>
                            <td>@employee.Age</td>
                            <td>@employee.Salary</td>
                        </tr>
                    }
                </tbody>
            </table>
        </div>
    </section>
}

Step 11: Insert Sample Data

You may want to insert some sample data to test the application.

1. Open the Application_Start method in Global.asax.cs and add the following code:

protected void Application_Start()
{
    AreaRegistration.RegisterAllAreas();
    FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
    RouteConfig.RegisterRoutes(RouteTable.Routes);
    BundleConfig.RegisterBundles(BundleTable.Bundles);

    using (var context = new ApplicationDbContext())
    {
        // Add a default employee
        var employee = new Employee
        {
            FirstName = "John",
            LastName = "Doe",
            Email = "john.doe@example.com",
            Age = 30,
            Salary = 50000
        };

        if (!context.Employees.Any(e => e.FirstName == "John" && e.LastName == "Doe"))
        {
            context.Employees.Add(employee);
            context.SaveChanges();
        }
    }
}

Step 12: Run the Application

1. Press F5 or click the Start button in Visual Studio to run your application.
2. Navigate to the home page (http://localhost:<port>/). You should see the list of employees displayed.

Summary

You have successfully created a DbContext and entities, enabled migrations, updated the database, created a controller and views, and inserted sample data in an ASP.NET MVC application using Entity Framework.