无法隐式转换类型“列表< AnonymousType＃1>'为“IEnumerable的< Models.APPLICANT>' [英] Cannot implicitly convert type 'List<AnonymousType#1>' to 'IEnumerable<Models.APPLICANT>'

问题描述

试图左联接表2

 公开的IEnumerable<申请人GT; GetApplicant（）
 {
 IEnumerable的<申请人GT; applicantdata = Cache.Get（申请人）为IEnumerable<申请人取代; 
 
 
如果（applicantdata == NULL）
 {在context.Profiles 
 
 
 VAR applicantList =（从连接上下文中的应用在a.PROFILE_ID .APPLICANTs 
等于app.Profile_id到joined.DefaultIfEmpty（）
从j加入
选择新的
 {
型材= A，$ b $ ; b申请人= j的，
 
 
}）以（1000）; 
 
 
 applicantdata = applicantList.AsQueryable（）排序依据（V => v.APPLICANT_ID）。.ToList（）; 
如果（applicantdata.Any（））
 {
 Cache.Set（申请人，applicantdata，30）; 
} 
} 
返回applicantdata; 
 
} 
  

但问题是，在最后一行有IM错误

  applicantdata = applicantList.AsQueryable（）排序依据（v => v.APPLICANT_ID）。.ToList（）; 
  

错误说

错误1无法隐式转换类型 System.Collections.Generic.List< AnonymousType＃1> 到 System.Collections.Generic .IEnumerable< Models.APPLICANT> 。一个显式转换存在（是否缺少强制）

这是我的申请人CLASS

  [DataContract（IsReference =真）] 
公共部分类申请人
 {
 [数据成员] 
公众诠释APPLICANT_ID {得到;组; } 
 [数据成员] 
公共字符串APPLICANT_LastName {搞定;组; } 
 [数据成员] 
公共字符串APPLICANT_FirstName {搞定;组; } 
 [数据成员] 
公共字符串APPLICANT_MiddleName {搞定;组; } 
 [数据成员] 
公共字符串APPLICANT_Address {搞定;组; } 
 [数据成员] 
公共字符串APPLICANT_City {搞定;组; } 
 [数据成员] 
公共字符串APPLICANT_Phone {搞定;组; } 
 [数据成员] 
公共字符串APPLICANT_Email {搞定;组; } 
 [数据成员] 
公众可空< INT> PROFILE_ID {搞定;组; } 
  

解决方案

这是藏品的类型是。问题

 的IEnumerable<申请人GT; applicantdata ... 
  

不等于你从这个表达式得到的类型：

  VAR applicantList = 
（从在context.Profiles 
加入context.APPLICANTs 
的应用程序上。 PROFILE_ID等于app.Profile_id到joined.DefaultIfEmpty（）
从j加入
选择新//<  - 这就是dicides的applicationList 
的类型{
简介= A，
申请人= j的，
}）以（1000）; 
  

这意味着你不能做到这一点：

  applicantdata = applicantList ... 
  

我想你需要做这样的事情：

  applicantdata = applicantList 
 .SelectMany（C => c.APPLICANTs）//该行补充
 .AsQueryable（）排序依据（v => v.APPLICANT_ID）。.ToList（）; 
  

更新

如果您使用的是我的解决方案与的SelectMany ，你应该问自己 - 我是否提取正确的数据，当我创建 applicationList < ？/ code>。

这也许是更好的..：

  VAR applicantList = 
（从在context.Profiles 
在a.PROFILE_ID context.APPLICANTs 
加入应用等于app.Profile_id到从j加入
在joined.DefaultIfEmpty（）
选择j可//<  - 这是申请人输入
}）以（1000）。 
  

Trying To Left Join 2 Tables

 public IEnumerable<APPLICANT> GetApplicant()
        {
            IEnumerable<APPLICANT> applicantdata = Cache.Get("applicants") as IEnumerable<APPLICANT>;


        if (applicantdata == null)
        {

            var applicantList = (from a in context.Profiles
                                 join app in context.APPLICANTs
                                     on a.PROFILE_ID equals app.Profile_id into joined
                                 from j in joined.DefaultIfEmpty()
                                 select new
                                            {
                                                Profiles = a,
                                                APPLICANTs= j,


                                    }).Take(1000);


            applicantdata = applicantList.AsQueryable().OrderBy(v => v.APPLICANT_ID).ToList(); 
            if (applicantdata.Any())
            {
                Cache.Set("applicants", applicantdata, 30);
            }
        }
        return applicantdata;

    }

But the problem is that im having error at the last Line

applicantdata = applicantList.AsQueryable().OrderBy(v => v.APPLICANT_ID).ToList();

The error says

Error 1 Cannot implicitly convert type 'System.Collections.Generic.List<AnonymousType#1>' to 'System.Collections.Generic.IEnumerable<Models.APPLICANT>'. An explicit conversion exists (are you missing a cast)

THIS IS MY APPLICANT CLASS

[DataContract(IsReference = true)]
public partial class APPLICANT
{
    [DataMember]
    public int APPLICANT_ID { get; set; }
    [DataMember]
    public string APPLICANT_LastName { get; set; }
    [DataMember]
    public string APPLICANT_FirstName { get; set; }
    [DataMember]
    public string APPLICANT_MiddleName { get; set; }
    [DataMember]
    public string APPLICANT_Address { get; set; }
    [DataMember]
    public string APPLICANT_City { get; set; }
    [DataMember]
    public string APPLICANT_Phone { get; set; }
    [DataMember]
    public string APPLICANT_Email { get; set; }
    [DataMember]
    public Nullable<int> Profile_id { get; set; }

解决方案

It is the type of the collections that is the problem.

 IEnumerable<APPLICANT> applicantdata ...

is not equal to the type you get from this expression:

 var applicantList =
    (from a in context.Profiles
     join app in context.APPLICANTs
        on a.PROFILE_ID equals app.Profile_id into joined
      from j in joined.DefaultIfEmpty()
     select new  //<-- this is what dicides the type of the applicationList
             {
                 Profiles = a,
                 APPLICANTs= j,
       }).Take(1000);

this mean that you cannot do this:

 applicantdata = applicantList...

I think you need to do something like this:

applicantdata = applicantList
                   .SelectMany(c => c.APPLICANTs) //this line added
                   .AsQueryable().OrderBy(v => v.APPLICANT_ID).ToList();

UPDATE

If you are using my "solution" with SelectMany, you should be asking yourself - "Am I extracting the right data when I create applicationList..?"

perhaps this is better..:

var applicantList =
    (from a in context.Profiles
     join app in context.APPLICANTs
        on a.PROFILE_ID equals app.Profile_id into joined
      from j in joined.DefaultIfEmpty()
     select j //<--  this is APPLICANTs type
       }).Take(1000);

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