Introduction

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

Create ASP.Net web application

Employee.cs

  1. using System;
  2. using System.Collections.Generic;
  3. using System.Linq;
  4. using System.Web;
  5. using System.ComponentModel.DataAnnotations;
  6. using System.ComponentModel.DataAnnotations.Schema;
  8. namespace Insert_Data___Code_Frist_Approach
  9. {
  10. public class Employee
  11. {
  13. public Employee()
  14. {
  15. }
  17. [Key]
  18. [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
  19. public int Id { get; set; }
  20. public string FirstName { get; set; }
  21. public string LastName { get; set; }
  22. public int Age { get; set; }
  23. }
  24. }
Employeecontext.cs
  1. using System;
  2. using System.Collections.Generic;
  3. using System.Data.Entity;
  4. using System.Linq;
  5. using System.Web;
  7. namespace Insert_Data___Code_Frist_Approach
  8. {
  9. public class EmployeeContext : DbContext
  10. {
  11. public EmployeeContext()
  12. : base("EmployeeConn")
  13. {
  14. Database.SetInitializer<EmployeeContext>(new CreateDatabaseIfNotExists<EmployeeContext>());
  15. }
  17. public DbSet<Employee> Employees { get; set; }
  18. }
  19. }
Web.config
  1. <connectionStrings>
  2. <add name="EmployeeConn"
  3. connectionString="Data Source=WIN-B4KJ8JI75VF;Initial Catalog=EmployeeDB;Integrated Security=true"
  4. providerName="System.Data.SqlClient"/>
  5. </connectionStrings>

Webform1.aspx

  1. <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="Select_Data___EF_Code_First_Approach.WebForm1" %>
  3. <!DOCTYPE html>
  5. <html xmlns="http://www.w3.org/1999/xhtml">
  6. <head runat="server">
  7. <title></title>
  8. </head>
  9. <body>
  10. <form id="form1" runat="server">
  11. <div>
  12. <table>
  13. <tr>
  14. <td>
  15. <asp:Label ID="Label1" runat="server" Text="Select Data - EF Code First Approach" Font-Bold="true"></asp:Label>
  16. </td>
  17. </tr>
  18. </table>
  19. <br />
  20. <br />
  21. <table>
  22. <tr>
  23. <td colspan="2">
  24. <asp:Button ID="Button1" runat="server" Text="Select Data"
  25. BackColor="Orange" Font-Bold="true" OnClick="Button1_Click" />
  26. <br />
  27. <br />
  28. </td>
  29. </tr>
  30. <tr>
  31. <td>
  32. <asp:GridView ID="GridView1" runat="server" BackColor="#DEBA84" BorderColor="#DEBA84" BorderStyle="None" BorderWidth="1px" CellPadding="3" CellSpacing="2">
  33. <FooterStyle BackColor="#F7DFB5" ForeColor="#8C4510"></FooterStyle>
  35. <HeaderStyle BackColor="#A55129" Font-Bold="True" ForeColor="White"></HeaderStyle>
  37. <PagerStyle HorizontalAlign="Center" ForeColor="#8C4510"></PagerStyle>
  39. <RowStyle BackColor="#FFF7E7" ForeColor="#8C4510"></RowStyle>
  41. <SelectedRowStyle BackColor="#738A9C" Font-Bold="True" ForeColor="White"></SelectedRowStyle>
  43. <SortedAscendingCellStyle BackColor="#FFF1D4"></SortedAscendingCellStyle>
  45. <SortedAscendingHeaderStyle BackColor="#B95C30"></SortedAscendingHeaderStyle>
  47. <SortedDescendingCellStyle BackColor="#F1E5CE"></SortedDescendingCellStyle>
  49. <SortedDescendingHeaderStyle BackColor="#93451F"></SortedDescendingHeaderStyle>
  50. </asp:GridView>
  53. </td>
  54. </tr>
  55. </table>
  57. </div>
  58. </form>
  59. </body>
  60. </html>
Webform1.aspx.cs
  1. using System;
  2. using System.Collections.Generic;
  3. using System.Linq;
  4. using System.Web;
  5. using System.Web.UI;
  6. using System.Web.UI.WebControls;
  8. namespace Select_Data___EF_Code_First_Approach
  9. {
  10. public partial class WebForm1 : System.Web.UI.Page
  11. {
  12. protected void Page_Load(object sender, EventArgs e)
  13. {
  15. }
  17. protected void Button1_Click(object sender, EventArgs e)
  18. {
  19. EmployeeContext empContext = new EmployeeContext();
  20. var query = from r in empContext.Employees select r;
  21. GridView1.DataSource = query.ToList();
  22. GridView1.DataBind();
  23. }
  24. }
  25. }
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!