MvcScaffolding: OnetoMany Relationships

安装更新 MvcScaffolding

Update-Package MvcScaffolding

Install-Package MvcScaffolding

定义一个Team与Player一对多的关系

 创建一个小组实体类

public class Team
{
    public int TeamId { get; set; }
    [Required] public string Name { get; set; }
    public string City { get; set; }
    public DateTime Founded { get; set; }
}

加入一个球员与小组的关系

public class Player
{
    public int PlayerId { get; set; }
    public string Name { get; set; }
 
    // Having a property called <entity>Id defines a relationship
    public int TeamId { get; set; }
}

通过http://....../Team创建几个小组

通过http://..../Playser建立几个球员，创建时选择球队。

通过以上方式创建的代码，不能查看球队里边球员，原因是Team与Player没有建立关系

更新Player代码如下，告诉player属于球队

public class Player
{
    public int PlayerId { get; set; }
    public string Name { get; set; }
    public int TeamId { get; set; }
 
    public virtual Team Team { get; set; } // This is new
}

virtual使用该属性实现延迟加载，相关的实体内容根据需要被提取

Team中有球员的属性

public class Team
{
    public int TeamId { get; set; }
    [Required] public string Name { get; set; }
    public string City { get; set; }
    public DateTime Founded { get; set; }
 
    public virtual ICollection<player> Players { get; set; } // This is new
}

通过如下命令创建

Scaffold Controller Team -Force
Scaffold Controller Player -Force

预先加载和SELECT N +1

// This is on PlayersController
public ViewResult Index()
{
    return View(context.Players.Include(player => player.Team).ToList());
}

仓储模式

Scaffold Controller Team -Repository -Force
Scaffold Controller Player -Repository -Force

public PlayersController(ITeamRepository teamRepository, IPlayerRepository playerRepository)
{
    this.teamRepository = teamRepository;
    this.playerRepository = playerRepository;
}

// This is on PlayersController
public ViewResult Index()
{
    return View(playerRepository.GetAllPlayers(player => player.Team));
}

定义更复杂的模型类之间的关系

public class Player
{
    public int PlayerId { get; set; }
    public string Name { get; set; }
 
    // This links Player to Team
    public int TeamId { get; set; }
}

public class Team
{
    public int TeamId { get; set; }
    // ... other Team properties go here
 
    // Each Team has an optional "next opponent" which is another Team
    public int? NextOpponentId { get; set; }
    [ForeignKey("NextOpponentId")] public virtual Team NextOpponent { get; set; }
 
    // Each Team also has a required Manager and Administrator, both of which are people
    public int ManagerId { get; set; }
    public int AdministratorId { get; set; }
    [ForeignKey("ManagerId")] public virtual Person Manager { get; set; }
    [ForeignKey("AdministratorId")] public virtual Person Administrator { get; set; }
}