MVC中使用FluentAPI

1.首先引入EF,并在数据库中创建好test1数据库，在配置文件中配置好数据库连接字符串

2.创建实体类

namespace FluentApi
{
    public class Person
    {
        public long Id { get; set; }
        public string Name { get; set; }
        public int Age { get; set; }
    }
}

3.创建数据库上下文对象

using System.Data.Entity;
using System.Reflection;

namespace FluentApi
{
    /// <summary>
    ///     创建数据库上下文对象
    /// </summary>
    public class TestContext : DbContext
    {
        public TestContext() : base("name=conn1")
        {
        }

        public DbSet<Person> Persons { get; set; }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);
            modelBuilder.Configurations.AddFromAssembly(Assembly.GetExecutingAssembly());
        }
    }
}

4.使用FluentAPI配置数据库表

using System.Data.Entity.ModelConfiguration;

namespace FluentApi.EntityConfig
{
    /// <summary>
    ///     使用FluentAPI配置数据库表
    /// </summary>
    public class PersonConfig : EntityTypeConfiguration<Person>
    {
        public PersonConfig()
        {
            ToTable("T_Persons");
            Property(e => e.Name).HasMaxLength(20).IsRequired();
        }
    }
}

5.调用的主程序

using System;
using System.Data.Entity.Validation;

namespace FluentApi
{
    /// <summary>
    ///     使用FluentAPI配置数据库表
    /// </summary>
    internal class Program
    {
        private static void Main()
        {
            Console.Title = "FluentAPI";

            UserFluentApi();

            Console.ReadKey();
        }

        private static void UserFluentApi()
        {
            using (var context = new TestContext())
            {
                var p = new Person
                {
                    Age = 30,
                    Name = "LDH"
                    //Name = "LDH88888888888888888888888888888888888888" // 错误：Name,字段 Name 必须是最大长度为“20”的字符串或数组类型。
                };
                context.Persons.Add(p);

                try
                {
                    context.SaveChanges();
                    Console.WriteLine("创建成功！");
                }
                catch (DbEntityValidationException ex)
                {
                    foreach (var err in ex.EntityValidationErrors)
                    foreach (var ve in err.ValidationErrors)
                        Console.WriteLine("错误：" + ve.PropertyName + "," + ve.ErrorMessage);
                }
            }
        }
    }
}

6.生成的数据库表