MVC3 LINQ加入 [英] MVC3 linq joins

问题描述

作为一个新手我试图在MVC3，剃须刀，EF我的手我有我想从产生它的景色三连表。在一个傻瓜的短暂以下是关于表

PJUsers - ID，memUID（从会员这个唯一的ID），名字，姓氏

PJAwards - 用户提名另一用户的一个奖项，以awardtypesID这个链接作为外键（awardId，BOOL：awardok）

PJAwartypes - （awardtypeID，awardName）

在控制器中的查询是这样的。

  VAR名单=
从db.PJawards TL
加入ü在tl.nomineeId db.PJUsers等于u.ID到tl_u
加入我在tl.nominatorId db.PJUsers等于i.MemUID到tl_i
其中，tl.awardOk
排序依据tl.awardDated上升从u在tl_u.DefaultIfEmpty（）
从我tl_i.DefaultIfEmpty（）
新选择
{
   状态= tl.awardOk，
    nomineeFname = u.FirstName，
    nomineeLname = u.LastName，
    奖= tl.PJawards.awardName，
    日= tl.awardDated，
    nominatorFname = i.FirstName，
    nominatorLname = i.LastName，
    nomineeCountry = u.Citizen，
    nomineeResidence = u.Residence，
    awardtypeId = tl.ID
};
 

某处我读，我必须构建在控制器类似查询模型类

  {
公共类AwardUserInfo
{
    公共AwardUserInfo（）{}
    公共BOOL状态{搞定;组; }
    公共字符串nomineeFname {搞定;组; }
    公共字符串nomineeLname {搞定;组; }
    公共字符串奖{搞定;组; }
    公共字符串在{搞定;组; }
    公共字符串nominatorFname {搞定;组; }
    公共字符串nominatorLname {搞定;组; }
    公共字符串nomineeCountry {搞定;组; }
    公共字符串nomineeResidence {搞定;组; }
    公众诠释awardtypeId {搞定;组; }}
}
 

请我学会这样的例子，能够帮助我以为我什么都不知道。

解决方案

  

某处我读，我必须构建在控制器类似查询模型类

尝试这个。

我猜你的EF-模型类似于

所以，你可以创建一个视图模型类

 公共类PJAwardsViewModel
{
    公众诠释标识{搞定;组; }
    公共字符串NominatorFName {搞定;组; }
    公共字符串NomineeFname {搞定;组; }
    公共字符串AwardName {搞定;组; }
    公共BOOL IsAwarded {搞定;组; }
}
 

如果你添加一些服务类这将是还不错

 公共类PJAwardsService
{
    公共静态列表＆LT; PJAwards＆GT;得到所有（）
    {
        使用（VAR上下文=新YourDBEntities（））
        {
            返回context.PJAwards
                .INCLUDE（X =＆GT; x.PJUsers）
                .INCLUDE（X =＆GT; x.PJUsers1）
                .INCLUDE（X =＆GT; x.PJAwartypes）.ToList（）;
        }
    }
}
 

（不要忘了写使用System.Data.Entity的; ）

然后，您可以添加一个ViewModelHelper类

 公共类PJAwardsViewModelHelper
{
    公共静态PJAwardsViewModel PopulatePJAwardsViewModel（PJAwards pjaward）
    {
        返回新PJAwardsViewModel
        {
            ID = pjaward.Id，
            NominatorFName = pjaward.PJUsers.FirstName，
            NomineeFname = pjaward.PJUsers1.FirstName，
            AwardName = pjaward.PJAwartypes.AwardName，
            IsAwarded = pjaward.IsAwarded
        };
    }    公共静态列表＆LT; PJAwardsViewModel＆GT; PopulatePJAwardsViewModelList（列表＆LT; PJAwards＆GT; pjawardsList）
    {
        返回pjawardsList.Select（X =＆GT; PopulatePJAwardsViewModel（X））。了ToList（）;
    }
}
 

在结束您的控制器指数方法看起来像这样

 公众的ActionResult指数（）
{
    变种pjawards = PJAwardsViewModelHelper.PopulatePJAwardsViewModelList（PJAwardsService.GetAll（）了ToList（））;
    返回查看（pjawards）;
}
 

你唯一应该做的就是添加一个视图（前建项目）。选择 PJAwardsViewModel 为 Model类和列表为脚手架模板。
享受它。

As a novice am trying my hands on MVC3,razor, EF I have Three connected Tables that I want to produce a view from it. In a simpleton's brief the following are about the tables

PJUsers - ID, memUID(this unique Id from membership),FirstName,LastName

PJAwards - user nominates another user for an award, this links with awardtypesID as foreign key ( awardId,bool:awardok)

PJAwartypes - (awardtypeID, awardName)

The query in the controller is like this

    var lists =
from tl in db.PJawards
join u in db.PJUsers on tl.nomineeId equals u.ID into tl_u
join i in db.PJUsers on tl.nominatorId equals i.MemUID into tl_i
where tl.awardOk 
orderby tl.awardDated ascending

from u in tl_u.DefaultIfEmpty()
from i in tl_i.DefaultIfEmpty()
select new
{
   Status = tl.awardOk,
    nomineeFname = u.FirstName,
    nomineeLname = u.LastName,
    award =  tl.PJawards.awardName,
    Dated = tl.awardDated,
    nominatorFname = i.FirstName,
    nominatorLname = i.LastName,
    nomineeCountry = u.Citizen,
    nomineeResidence = u.Residence,
    awardtypeId = tl.ID
};

somewhere i read that i have to construct a model class similar to the query in the controller

{
public class AwardUserInfo
{
    public AwardUserInfo() { }
    public bool Status { get; set; }
    public string nomineeFname { get; set; }
    public string nomineeLname { get; set; }
    public string award { get; set; }
    public string Dated { get; set; }
    public string nominatorFname { get; set; }
    public string nominatorLname { get; set; }
    public string nomineeCountry { get; set; }
    public string nomineeResidence { get; set; }
    public int awardtypeId { get; set; }

}
}

Please I learn by examples so to be able to help me assume I don't know anything

解决方案

somewhere i read that i have to construct a model class similar to the query in the controller

Try this.

I guess your ef-model is similar to

So You can create a ViewModel class

public class PJAwardsViewModel
{
    public int Id { get; set; }
    public string NominatorFName { get; set; }
    public string NomineeFname { get; set; }
    public string AwardName { get; set; }
    public bool IsAwarded { get; set; }
} 

It will be also good if You add some service class

public class PJAwardsService
{
    public static List<PJAwards> GetAll()
    {
        using (var context = new YourDBEntities())
        {
            return context.PJAwards
                .Include(x => x.PJUsers)
                .Include(x => x.PJUsers1)
                .Include(x => x.PJAwartypes).ToList();
        }
    }
}

(Don't forget to write using System.Data.Entity; )

Then You can add a ViewModelHelper class

public class PJAwardsViewModelHelper
{
    public static PJAwardsViewModel PopulatePJAwardsViewModel(PJAwards pjaward)
    {
        return new PJAwardsViewModel
        {
            Id = pjaward.Id,
            NominatorFName = pjaward.PJUsers.FirstName,
            NomineeFname = pjaward.PJUsers1.FirstName,
            AwardName = pjaward.PJAwartypes.AwardName,
            IsAwarded = pjaward.IsAwarded
        };
    }

    public static List<PJAwardsViewModel> PopulatePJAwardsViewModelList(List<PJAwards> pjawardsList)
    {
        return pjawardsList.Select(x => PopulatePJAwardsViewModel(x)).ToList();
    }
}

At the end Your controller index method will look like this

public ActionResult Index()
{
    var pjawards = PJAwardsViewModelHelper.PopulatePJAwardsViewModelList(PJAwardsService.GetAll().ToList());
    return View(pjawards);
}  

The only thing You should do is add a view (build the project before). Choose PJAwardsViewModel as a Model class and List as a scaffold template. Enjoy it.

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