protected override void Seed(ManyToManyRemoveContext context)
{
var roles = new List<Role> {
new Role{ Id=1,Name="超级管理员" },
new Role{ Id=2,Name="管理员" },
new Role{ Id=3,Name="一般用户" }
};

var users = new List<User> {
new User {Id=1,FirstName="Kobe",LastName="Bryant",CreatedOn=DateTime.Now,Roles=roles },
new User {Id=2,FirstName="Chris",LastName="Paul",CreatedOn=DateTime.Now,Roles=roles.Where(x=>x.Id==2).ToList() },
new User {Id=3,FirstName="Jerimy",LastName="Lin",CreatedOn=DateTime.Now,Roles=roles.Take(2).ToList() }
};
}
}
}

public partial class Init : DbMigration
{
public override void Up()
{
CreateTable(
"dbo.Role",
c => new
{
Id = c.Int(nullable: false, identity: true),
Name = c.String(nullable: false, maxLength: 50),
})
.PrimaryKey(t => t.Id);

CreateTable(
"dbo.User",
c => new
{
Id = c.Int(nullable: false, identity: true),
FirstName = c.String(nullable: false, maxLength: 50),
LastName = c.String(nullable: false, maxLength: 50),
CreatedOn = c.DateTime(),
})
.PrimaryKey(t => t.Id);

CreateTable(
"dbo.LNK_User_Role",
c => new
{
RoleId = c.Int(nullable: false),
UserId = c.Int(nullable: false),
})
.PrimaryKey(t => new { t.RoleId, t.UserId })
.ForeignKey("dbo.Role", t => t.RoleId, cascadeDelete: true)
.ForeignKey("dbo.User", t => t.UserId, cascadeDelete: true)
.Index(t => t.RoleId)
.Index(t => t.UserId);

}

public override void Down()
{
DropForeignKey("dbo.LNK_User_Role", "UserId", "dbo.User");
DropForeignKey("dbo.LNK_User_Role", "RoleId", "dbo.Role");
DropIndex("dbo.LNK_User_Role", new[] { "UserId" });
DropIndex("dbo.LNK_User_Role", new[] { "RoleId" });
DropTable("dbo.LNK_User_Role");
DropTable("dbo.User");
DropTable("dbo.Role");
}
}
}

static void Query()
{
using (var cxt = new ManyToManyRemoveContext())
{
var users = cxt.Users.ToList();
users.ForEach(x =>
{
WriteLine("User First Name:{0},Last Name:{1},Create On:{2}\n |__Roles:{3}", x.FirstName, x.LastName, x.CreatedOn, string.Join(",", x.Roles.Select(r => r.Name)));
});
}
}

static void Query()
{
using (var cxt = new ManyToManyRemoveContext())
{
var users = cxt.Users.ToList();
users.ForEach(x =>
{
WriteLine("User First Name:{0},Last Name:{1},Create On:{2}\n |__Roles:{3}", x.FirstName, x.LastName, x.CreatedOn, string.Join(",", x.Roles.Select(r => r.Name)));
});
}
}

static void Update()
{
using (var cxt = new ManyToManyRemoveContext())
{
var user = cxt.Users.FirstOrDefault(x=>x.Id==3);
user.FirstName = "ShuHao";
cxt.SaveChanges();
}
}

namespace EFRemoveManyToManyDemo
{
public class Program
{
static void Main(string[] args)
{
//Update();
WriteLine("Before many to many removed");
Query();
RemoveManyToMany();
WriteLine("After many to many removed");
Query();
ReadKey();
}

static void Query()
{
using (var cxt = new ManyToManyRemoveContext())
{
var users = cxt.Users.ToList();
users.ForEach(x =>
{
WriteLine("User First Name:{0},Last Name:{1},Create On:{2}\n |__Roles:{3}", x.FirstName, x.LastName, x.CreatedOn, string.Join(",", x.Roles.Select(r => r.Name)));
});
}
}

static void Add()
{
List<Role> roles;
using (var cxt = new ManyToManyRemoveContext())
{
roles = cxt.Roles.ToList();
cxt.Users.Add(new User
{
Id = 4,
FirstName = "Console",
LastName = "App",
CreatedOn = DateTime.Now,
Roles = roles.Where(x => x.Id == 1).ToList()
});
}
}

static void Update()
{
using (var cxt = new ManyToManyRemoveContext())
{
var user = cxt.Users.FirstOrDefault(x => x.Id == 3);
user.FirstName = "ShuHao";
cxt.SaveChanges();
}
}

static void Remove()
{
using (var cxt = new ManyToManyRemoveContext())
{
var user = cxt.Users.FirstOrDefault(x => x.Id == 2);
cxt.Users.Remove(user);
cxt.SaveChanges();
}
}

static void RemoveManyToMany()
{
using (var cxt = new ManyToManyRemoveContext())
{
var user = cxt.Users.FirstOrDefault(x => x.Id == 1);
var roles = new List<Role>();
roles.AddRange(user.Roles.Select(x => x));
foreach (var role in roles)
{
user.Roles.Remove(role);
}
cxt.Users.Remove(user);
cxt.SaveChanges();
}
}
}
}