EF Core – Get Started 搭建单侧环境

有时候想搭个环境做测试, 又记不住那些 command, 官方教程又啰嗦. git clone 模板又不太好管理, 索性记入在这里吧.

创建项目

dotnet new webapp -o SimpleTestEFCore

for console app 的话

dotnet new console -o SimpleTestEFCore

Install NuGet

dotnet add package Microsoft.AspNetCore.Diagnostics.EntityFrameworkCore
dotnet add package Microsoft.EntityFrameworkCore.Design
dotnet add package Microsoft.EntityFrameworkCore.SqlServer
dotnet add package Microsoft.EntityFrameworkCore.Tools #(如果你要 F5 debug db.Database.Migrate(), 这个一定要装哦)

Files

Product.cs

namespace SimpleTestEFCore.Entity;

public class Product
{
    public int Id { get; set; }
    public string Name { get; set; } = "";
}

ApplicationDbContext.cs

using Microsoft.EntityFrameworkCore;

namespace SimpleTestEFCore.Entity;

public class ApplicationDbContext : DbContext
{
    public ApplicationDbContext(
       DbContextOptions<ApplicationDbContext> options
    ) : base(options)
    {
    }

    public DbSet<Product> Products => Set<Product>();
    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Product>().ToTable("Product");
        modelBuilder.Entity<Product>().Property(e => e.Name).HasMaxLength(256);
    }
}

for console app 的话，不需要 constructor 不需要传 options

appsettings.json

"ConnectionStrings": {
  "ApplicationDbContext": "Server=192.168.1.152;Database=SimpleTestEFCore;Trusted_Connection=True;MultipleActiveResultSets=true;TrustServerCertificate=True"
},

p.s. TrustServerCertificate=true 是 EF Core 7.0 之后才需要添加的 (算是 workaround, right way 是做 Certificate).

参考:

Github Issue – EFCore.SqlServer 6.0.1 Untrusted certificate authority error

Released: General Availability of Microsoft.Data.SqlClient 4.0

Stack Overflow – "The certificate chain was issued by an authority that is not trusted" when connecting DB in VM Role from Azure website

因为 EF Core 7.0 depend 了 Microsoft.Data.SqlClient 4.0 而 4.0 有一个 breaking changes Encrypt = true, by default. .

Program.cs

builder.Services.AddDbContext<ApplicationDbContext>(options =>
{
    options
        .UseSqlServer(builder.Configuration.GetConnectionString("ApplicationDbContext"))
        .LogTo(Console.WriteLine); // log sql query for easy debug
});

for console app 的话，不需要 appsettings.json, 和 Program.cs 的 setup，取而代之的是在 ApplicationDbContext overrde OnConfiguring 方法

public class ApplicationDbContext : DbContext
{
    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder
            .UseSqlServer("Server=192.168.1.152;Database=SimpleTestEFCore;Trusted_Connection=True;MultipleActiveResultSets=true;TrustServerCertificate=True")
            .LogTo(Console.WriteLine);
    }
}

cmd

dotnet ef migrations add init
dotnet ef database update

Index.cshtml.cs

using SimpleTestEFCore.Entity;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.EntityFrameworkCore;

namespace SimpleTestEFCore.Pages;

public class IndexModel : PageModel
{
    public async Task OnGetAsync([FromServices] ApplicationDbContext db)
    {
        var products = await db.Products.ToListAsync();
        db.Products.Add(new Product { Name = "Product1" });
        await db.SaveChangesAsync();
    }
}

想在 program.cs 注入也可以, 必须 CreateScope 哦.

var app = builder.Build();
using var scope = app.Services.CreateScope();
var db = scope.ServiceProvider.GetRequiredService<ApplicationDbContext>();
var person = new Person
{
    Name = "Derrick",
    Animals = new List<Animal>
    {
            new Dog { Name = "Dog1",  DogPrice = 100 },
            new Cat { Name = "Cat1",  CatPrice = 100 },
    }
};
db.People.Add(person);
await db.SaveChangesAsync();

for app console 的话

using EFCore.Entity;
using Microsoft.EntityFrameworkCore;

using var db = new ApplicationDbContext();
var products = await db.Products.ToListAsync();
Console.WriteLine(products.Count);