.NET Core连接数据库，.Net Core连接Mysql数据库

DbContext：这里设置自定义连接字符串的写法过时了。参考连接MySql的写法。

using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using System;
using WebApi.Models;

namespace WebApi.Data
{
    public class DataMgrContext : DbContext
    {
        public readonly static IConfiguration configuration;
        static DataMgrContext()
        {
            configuration = new ConfigurationBuilder()
            .SetBasePath(Environment.CurrentDirectory)
            .AddJsonFile("appsettings.json", true, true)
            .AddInMemoryCollection()
            .Build();
        }
        public static string connectionString
        {
            get { return configuration["ConnectionStrings:Default"]; }
        }

        public DataMgrContext(DbContextOptions<DataMgrContext> options)
            : base(options)
        {
        }
        public DataMgrContext() { }
        
        public DbSet<SysUser> SysUsers{ get; set; }
        public DbSet<Permission> Permissions { get; set; }
        public DbSet<Role> Roles { get; set; }
        public DbSet<RolePermission> RolePermissions { get; set; }
        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            //映射数据库表名
            //modelBuilder.Entity<Role>().ToTable("Role");
        }
        protected override void OnConfiguring(DbContextOptionsBuilder options)
        {
            options.UseSqlServer(connectionString);
        }
    }
}

appSettings.json

"ConnectionStrings": {
    "Default": "Data Source=.;Initial Catalog=efcoretest;User ID=sa;Password=111111"
  },

Startup.cs

public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext<DataMgrContext>();//注入数据库服务
    //...
}

　　使用

using (var db = new DataMgrContext())
{
    db.Blogs.Add(dto);
    db.SaveChanges();
}

//2
private readonly DataMgrContext db;
public BlogController(DataMgrContext context)
{
    db = context;
}

.Net Core连接Mysql数据库，以下是用的VS2022最新版，所以注入DbContext是在Program.cs中，大差不差。
引入NuGet包：Microsoft.EntityFrameworkCore，Microsoft.EntityFrameworkCore.Tools，Microsoft.Extensions.Configuration，MySql.EntityFrameworkCore
DAO层，DbContext

using Microsoft.EntityFrameworkCore;
namespace dao
{
    public class MysqlDataContext : DbContext
    {
        public MysqlDataContext(DbContextOptions<MysqlDataContext> options)
           : base(options)
        {
            
        }
        public DbSet<Payment> Payment { get; set; }
    }
}

 DAO实体

using System.ComponentModel.DataAnnotations.Schema;
namespace dao
{
    [Table("payment")]
    public class Payment
    {
        [Column("id")]
        public int Id { get; set; }
        [Column("serial")]
        public string? Serial { get; set; }
    }
}

 DAO Service，IPaymentService 是自定义的接口

namespace dao
{
    public class PaymentService : IPaymentService
    {
        private MysqlDataContext _mysqlDataContext;
        public PaymentService(MysqlDataContext mysqlDataContext)
        {
            _mysqlDataContext = mysqlDataContext;
        }
        public List<Payment> GetList()
        {
            return _mysqlDataContext.Payment.ToList();
        }
    }
}

　　Web项目 appsettings.json

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft.AspNetCore": "Warning"
    }
  },
  "AllowedHosts": "*",
  "ConnectionStrings": {
    "Default": "默认连接字符串，也可使用新的，支持多库",
    "MysqlContext": "server=localhost;port=3306;database=springcloudtest;uid=root;pwd=root123;CharSet=utf8;SslMode=none;AllowPublicKeyRetrieval=True;"
  }
}

　　Web项目 Program.cs

//连接数据库，多数据库，直接新建多个DataContext就行了。
builder.Services.AddDbContext<MysqlDataContext>(options =>
{
    string connStr = builder.Configuration.GetConnectionString("MysqlContext") + "";
    options.UseMySQL(connStr);
});

#region 自定义服务
builder.Services.AddScoped<IPaymentService, PaymentService>();
#endregion

　　最后使用

public class HomeController : Controller
{
    private IPaymentService _paymentService;
    public HomeController(IPaymentService paymentService)
    {
        _paymentService = paymentService;
    }
    public IActionResult Index()
    {
        var list = _paymentService.GetList();
        ViewData["list"] = list;
        return View();
    }
}