Entity Framework 方法组包含不起作用

Question

我在使用 EF 中的方法组加载相关实体时遇到了一些问题。

在简单查询中，加载相关实体 与 Include 一起工作正常。

例如：

var result =
    Repository.Query<TimeState>(x => x.Accepted == 0 && x.ProjectID != null && myTeam.Contains(x.EmployeeID))
                       .Include(typeof(Project).Name)
                       .Include(typeof(Employee).Name)
                       .Include(typeof(EmployeeDetails).Name)
                       .OrderByDescending(x => x.SubmitedDate);

工作完美，加载项目和员工

但在下一个查询中没有加载项目和员工

var result2 = from item in Repository.Query<TimeState>(x => x.Accepted == 0 && x.ProjectID != null)
                                               .Include(typeof(Project).Name)
                                               .Include(typeof(Employee).Name)
                                               .Include(typeof(EmployeeDetails).Name)
               let projectId = (int)item.ProjectID
               let isA = projectsIds.Contains(projectId) && item.Employee.EmployeeDetails.SuperiorID == id
               let isB = item.Project.ManagerID == id && employeesTeam.Contains(item.EmployeeID)
               where isA || isB
               orderby item.SubmitedDate descending
               select item;

我试着做了这样的改变：select new { item, item.Employee, item.Project };

var result3 = from item in Repository.Query<TimeState>(x => x.Accepted == 0 && x.ProjectID != null)
                                               .Include(typeof(Project).Name)
                                               .Include(typeof(Employee).Name)
                                               .Include(typeof(EmployeeDetails).Name)
               let projectId = (int)item.ProjectID
               let isA = projectsIds.Contains(projectId) && item.Employee.EmployeeDetails.SuperiorID == id
               let isB = item.Project.ManagerID == id && employeesTeam.Contains(item.EmployeeID)
               where isA || isB
               orderby item.SubmitedDate descending
               select new { item, item.Employee, item.Project };

在那之后，result3[0].Employee 有一个值，与 result3[0].Project（或该集合中的任何其他项目）相同。
问题是我不需要将 Employee 和 Project 作为此动态对象 result3 中的单独属性。

returnsresult2 方法中怎么可能有 Employee 和 Project？ :)

Answer 1

我很少使用查询语法，而且我从来没有运行接触过使用 .Include(typeof(..).Name) 语法的人，所以请尝试以下操作：

var result2 = (from item in Repository.Query<TimeState>(x => x.Accepted == 0 && x.ProjectID != null)
               let projectId = (int)item.ProjectID
               let isA = projectsIds.Contains(projectId) && item.Employee.EmployeeDetails.SuperiorID == id
               let isB = item.Project.ManagerID == id && employeesTeam.Contains(item.EmployeeID)
               where isA || isB
               orderby item.SubmitedDate descending
               select item)
  .Include(i=>i.Projects)
  .Include(i=>i.Employees)
  .Include(i=>i.EmployeeDetails);

您可能还需要包含 using System.Data.Entity; 才能正常工作。

Entity Framework 方法组包含不起作用

Entity Framework method group Include does not work

c#

entity-framework

linq

eager-loading

method-group