.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。

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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

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

Startup.cs

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

　　使用

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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

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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

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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

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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

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{   "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

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//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

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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();     } }