使用nuget 添加EntityFramework 引用

引入命名空間

using System.Data.Entity;
using System.Data.Entity.Migrations;

關(guān)鍵代碼

internal sealed class MainDbMigrationsConfiguration: DbMigrationsConfiguration<MainDbContext>
 {
    public MainDbMigrationsConfiguration()
     {
        //默認(rèn)情況下不會(huì)自動(dòng)遷移數(shù)據(jù)庫(kù)結(jié)構(gòu)
        //設(shè)置為true則自動(dòng)遷移數(shù)據(jù)庫(kù)結(jié)構(gòu)
         AutomaticMigrationsEnabled = true;
     }
}

完整的類(lèi)大概是這個(gè)樣子

using System.Data.Entity;
using System.Data.Entity.Migrations;

namespace ManageSystem.Core
{
    public class MainDbContext : DbContext
    {
        public MainDbContext() : base()
        {
            Database.SetInitializer<MainDbContext>(new MigrateDatabaseToLatestVersion<MainDbContext, MainDbMigrationsConfiguration>());
        }
        public MainDbContext(string connectionName) : base(connectionName)
        {
            Database.SetInitializer<MainDbContext>(new MigrateDatabaseToLatestVersion<MainDbContext, MainDbMigrationsConfiguration>());
        }
        internal sealed class MainDbMigrationsConfiguration: DbMigrationsConfiguration<MainDbContext>
        {
            public MainDbMigrationsConfiguration()
            {
                AutomaticMigrationsEnabled = true;
            }
        }
        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            modelBuilder.Conventions.Remove<System.Data.Entity.ModelConfiguration.Conventions.PluralizingTableNameConvention>();
        }
    }
}

這種方式主要是將原本獨(dú)立出來(lái)的類(lèi)合并到DbContext中來(lái).
更常規(guī)一點(diǎn)的做法是把下面這段代碼獨(dú)立出來(lái),放在一個(gè)類(lèi)里面方便后期維護(hù)

internal sealed class MainDbMigrationsConfiguration: DbMigrationsConfiguration<MainDbContext>
        {
            public MainDbMigrationsConfiguration()
            {
                AutomaticMigrationsEnabled = true;//任何Model Class的修改將會(huì)直接更新DB
                AutomaticMigrationDataLossAllowed = true;
            }
        }