Select Data Using Code First Approach

Introduction

This article shows how to select data using the Code First approach.

Create ASP.Net web application

Employee.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel.DataAnnotations.Schema;
namespace Insert_Data___Code_Frist_Approach
{
public class Employee
{
public Employee()
{
}
[Key]
[DatabaseGenerated(DatabaseGeneratedOption.Identity)]
public int Id { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public int Age { get; set; }
}
}

Employeecontext.cs

using System;
using System.Collections.Generic;
using System.Data.Entity;
using System.Linq;
using System.Web;
namespace Insert_Data___Code_Frist_Approach
{
public class EmployeeContext : DbContext
{
public EmployeeContext()
: base("EmployeeConn")
{
Database.SetInitializer<EmployeeContext>(new CreateDatabaseIfNotExists<EmployeeContext>());
}
public DbSet<Employee> Employees { get; set; }
}
}

Web.config

<connectionStrings>
<add name="EmployeeConn"
connectionString="Data Source=WIN-B4KJ8JI75VF;Initial Catalog=EmployeeDB;Integrated Security=true"
providerName="System.Data.SqlClient"/>
</connectionStrings>

Webform1.aspx

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="Select_Data___EF_Code_First_Approach.WebForm1" %>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<table>
<tr>
<td>
<asp:Label ID="Label1" runat="server" Text="Select Data - EF Code First Approach" Font-Bold="true"></asp:Label>
</td>
</tr>
</table>
<br />
<br />
<table>
<tr>
<td colspan="2">
<asp:Button ID="Button1" runat="server" Text="Select Data"
BackColor="Orange" Font-Bold="true" OnClick="Button1_Click" />
<br />
<br />
</td>
</tr>
<tr>
<td>
<asp:GridView ID="GridView1" runat="server" BackColor="#DEBA84" BorderColor="#DEBA84" BorderStyle="None" BorderWidth="1px" CellPadding="3" CellSpacing="2">
<FooterStyle BackColor="#F7DFB5" ForeColor="#8C4510"></FooterStyle>
<HeaderStyle BackColor="#A55129" Font-Bold="True" ForeColor="White"></HeaderStyle>
<PagerStyle HorizontalAlign="Center" ForeColor="#8C4510"></PagerStyle>
<RowStyle BackColor="#FFF7E7" ForeColor="#8C4510"></RowStyle>
<SelectedRowStyle BackColor="#738A9C" Font-Bold="True" ForeColor="White"></SelectedRowStyle>
<SortedAscendingCellStyle BackColor="#FFF1D4"></SortedAscendingCellStyle>
<SortedAscendingHeaderStyle BackColor="#B95C30"></SortedAscendingHeaderStyle>
<SortedDescendingCellStyle BackColor="#F1E5CE"></SortedDescendingCellStyle>
<SortedDescendingHeaderStyle BackColor="#93451F"></SortedDescendingHeaderStyle>
</asp:GridView>
</td>
</tr>
</table>
</div>
</form>
</body>
</html>

Webform1.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
namespace Select_Data___EF_Code_First_Approach
{
public partial class WebForm1 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
EmployeeContext empContext = new EmployeeContext();
var query = from r in empContext.Employees select r;
GridView1.DataSource = query.ToList();
GridView1.DataBind();
}
}
}

The following is the output of the application.

Summary

In this article, we saw how to select data using the Code First approach. Happy coding!