Seed ข้อมูลให้กับโปรเจ็กส์ WebApp

สร้างคลาส Data\SeedData.cs

Data\SeedData.cs

using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using System;
using System.Linq;
using WebApp.Data.Models;
using WebApp.Models;

namespace WebApp.Data
{
    public static class SeedData
    {
        public static void Initialize(IServiceProvider serviceProvider)
        {
            using (var context = new ApplicationDbContext(
                serviceProvider.GetRequiredService<DbContextOptions<ApplicationDbContext>>()))
            {
                // Look for any movies.
                if (context.Movie.Any())
                {
                    return;   // DB has been seeded
                }

                context.Movie.AddRange(
                    new Movie
                    {
                        Title = "When Harry Met Sally",
                        ReleaseDate = DateTime.Parse("1989-2-12"),
                        Genre = "Romantic Comedy",
                        Price = 7.99M
                    },

                    new Movie
                    {
                        Title = "Ghostbusters ",
                        ReleaseDate = DateTime.Parse("1984-3-13"),
                        Genre = "Comedy",
                        Price = 8.99M
                    },

                    new Movie
                    {
                        Title = "Ghostbusters 2",
                        ReleaseDate = DateTime.Parse("1986-2-23"),
                        Genre = "Comedy",
                        Price = 9.99M
                    },

                    new Movie
                    {
                        Title = "Rio Bravo",
                        ReleaseDate = DateTime.Parse("1959-4-15"),
                        Genre = "Western",
                        Price = 3.99M
                    }
                );
                context.SaveChanges();
            }
        }
    }
}

using Microsoft.EntityFrameworkCore;

using Microsoft.Extensions.DependencyInjection;

using System;

using System.Linq;

using WebApp.Data.Models;

using WebApp.Models;

namespace WebApp.Data

{

public static class SeedData

{

public static void Initialize(IServiceProvider serviceProvider)

{

using (var context = new ApplicationDbContext(

serviceProvider.GetRequiredService<DbContextOptions<ApplicationDbContext>>()))

{

// Look for any movies.

if (context.Movie.Any())

{

return; // DB has been seeded

}

context.Movie.AddRange(

new Movie

{

Title = "When Harry Met Sally",

ReleaseDate = DateTime.Parse("1989-2-12"),

Genre = "Romantic Comedy",

Price = 7.99M

new Movie

{

Title = "Ghostbusters ",

ReleaseDate = DateTime.Parse("1984-3-13"),

Genre = "Comedy",

Price = 8.99M

new Movie

{

Title = "Ghostbusters 2",

ReleaseDate = DateTime.Parse("1986-2-23"),

Genre = "Comedy",

Price = 9.99M

new Movie

{

Title = "Rio Bravo",

ReleaseDate = DateTime.Parse("1959-4-15"),

Genre = "Western",

Price = 3.99M

}

);

context.SaveChanges();

}

บรรทัดที่ 10 : SeedData เป็น Static คลาส
บรรทัดที่ 12 : Initialize() เป็น Static ฟังก์ชัน
บรรทัดที่ 18 : ตรวจสอบว่าตาราง Movie มีข้อมูลมั๊ย ถ้ามีก็ไม่ต้อง Seed

Program.cs

using Microsoft.AspNetCore;
using Microsoft.AspNetCore.Hosting;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using System;
using WebApp.Data;
using WebApp.Models;

namespace WebApp
{
    public class Program
    {
        public static void Main(string[] args)
        {
            //CreateWebHostBuilder(args).Build().Run();

            var host = CreateWebHostBuilder(args).Build();

            using (var scope = host.Services.CreateScope())
            {
                var services = scope.ServiceProvider;

                try
                {
                    var context = services.GetRequiredService<ApplicationDbContext>();
                    context.Database.Migrate();
                    SeedData.Initialize(services);
                }
                catch (Exception ex)
                {
                    var logger = services.GetRequiredService<ILogger<Program>>();
                    logger.LogError(ex, "An error occurred seeding the DB.");
                }
            }

            host.Run();
        }

        public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>
            WebHost.CreateDefaultBuilder(args)
                .UseStartup<Startup>();
    }
}

using Microsoft.AspNetCore;

using Microsoft.AspNetCore.Hosting;

using Microsoft.EntityFrameworkCore;

using Microsoft.Extensions.DependencyInjection;

using Microsoft.Extensions.Logging;

using System;

using WebApp.Data;

using WebApp.Models;

namespace WebApp

{

public class Program

{

public static void Main(string[] args)

{

//CreateWebHostBuilder(args).Build().Run();

var host = CreateWebHostBuilder(args).Build();

using (var scope = host.Services.CreateScope())

{

var services = scope.ServiceProvider;

try

{

var context = services.GetRequiredService<ApplicationDbContext>();

context.Database.Migrate();

SeedData.Initialize(services);

}

catch (Exception ex)

{

var logger = services.GetRequiredService<ILogger<Program>>();

logger.LogError(ex, "An error occurred seeding the DB.");

}

host.Run();

}

public static IWebHostBuilder CreateWebHostBuilder(string[] args) =>

WebHost.CreateDefaultBuilder(args)

.UseStartup<Startup>();

}

เปลี่ยนจาก Seed ที่ Startup.cs มา Seed ที่ Program.cs

รันกด F5

จะเห็นข้อมูลที่ Seed ไว้มาแสดง

Link

docs.microsoft.com – Work with SQL Server LocalDB and ASP.NET Core

Phaisarn Sutheebanjard

blog.phaisarn.com

Seed ข้อมูลให้กับโปรเจ็กส์ WebApp