2.EF Core添加数据库配置的几种方式

    public class BloggingContext: DbContext
    {
        /// <summary>
        /// 配置数据连接信息
        /// </summary>
        /// <param name="optionsBuilder"></param>
        protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
        {
            optionsBuilder.UseMySql("数据库连接字符串");
            base.OnConfiguring(optionsBuilder);
        }

    }

var optionsBuilder = new DbContextOptionsBuilder<BloggingContext>();
optionsBuilder.UseMySql("数据库连接字符串");
using (BloggingContext db=new BloggingContext(optionsBuilder.Options)) {
　　return db.Blogs;
}

    public  class BloggingContext : DbContext
    {
        /// <summary>
        /// 容器初始化时传入options
        /// </summary>
        /// <param name="options"></param>
        public BloggingContext(DbContextOptions<BloggingContext> options): base(options)
        {
        }

        public virtual DbSet<Blog> Blogs { get; set; }
        public virtual DbSet<Post> Posts { get; set; }
    }

         
services.AddDbContextPool<BloggingContext>(options => options.UseMySql("数据库连接字符串")); //会集成.net core 日志机制，微软推荐使用连接池的方式
      
services.AddDbContext<BloggingContext>(options=>options.UseMySql("数据库连接字符串"));

            using (var context = HttpContext.RequestServices.GetService<BloggingContext>())
            {
                // do stuff
            }

        public IActionResult Index([FromServices]BloggingContext context)
        {return Content(“”);
        }

    public class HomeController : Controller
    {
        private readonly BloggingContext _context;

        public HomeController(BloggingContext context)
        {
            _context = context;
        }
     }