linq-to-sql - 错误: The entity or complex type cannot be constructed in a LINQ to Entities query

Question

我收到此错误“System.NotSupportedException:无法在LINQ to Entities查询中构造实体或复杂类型'MyModel.Team'。”当我导航到“团队/索引/{id}”页面时。有人可以指出我所犯的错误吗？

Controller :

public ActionResult Index(int id)
    {
        IQueryable<Team> teams = teamRepository.GetTeamByPersonID(id);   
        return View("Index", teams);
    }

资料库:

public IQueryable<Team> GetTeamByPersonID(int id)
    {
        return from t in entities.Teams
               join d in entities.Departments
                on t.TeamID equals d.TeamID
               where (from p in entities.Person_Departments
                      join dep in entities.Departments
                      on p.DepartmentID equals dep.DepartmentID
                      where p.PersonID == id
                      select dep.TeamID).Contains(d.TeamID)
               select new Team
               {
                   TeamID = t.TeamID,
                   FullName = t.FullName,
                   ShortName = t.ShortName,
                   Iso5 = t.Iso5,
                   DateEstablished = t.DateEstablished,
                   City = t.City,
                   CountryID = t.CountryID
               };
    }

ViewModel:

public IQueryable<Team> teamList { get; set; }
public TeamViewModel(IQueryable<Team> teams)
    {
         teamList = teams;
    }

看法:

<% foreach (var team in Model){ %>
    <tr>
        <td><%: Html.ActionLink(team.ShortName, "Details", new { id=team.TeamID}) %></td>
        <td><%: team.City %></td>
        <td><%: team.Country %></td>
    </tr>
<% } %>

Answer 1

问题是您正在Team语句中创建select类，而LINQ to SQL不支持该类。将您的select更改为:

select t

或使用匿名类型:

select new
{
    TeamID = t.TeamID,
    FullName = t.FullName,
    ShortName = t.ShortName,
    Iso5 = t.Iso5,
    DateEstablished = t.DateEstablished,
    City = t.City,
    CountryID = t.CountryID
};

或使用DTO(任何非实体的实体):

select new TeamDTO
{
    TeamID = t.TeamID,
    FullName = t.FullName,
    ShortName = t.ShortName,
    Iso5 = t.Iso5,
    DateEstablished = t.DateEstablished,
    City = t.City,
    CountryID = t.CountryID
};