我怎么能。在LINQ中包含多个级别?
我有以下课程:
public class Problem : AuditableTable { public Problem() { this.Questions = new List(); } public int ProblemId { get; set; } public string Title { get; set; } public virtual ICollection Questions { get; set; } } public Question() { this.Answers = new List(); } public int QuestionId { get; set; } public int ProblemId { get; set; } public virtual ICollection Answers { get; set; } public virtual Problem Problem { get; set; } } public class Answer : AuditableTable { public int AnswerId { get; set; } public int QuestionId { get; set; } public string Text { get; set; } public virtual Question Question { get; set; } }
我想发出这样的查询:
var problems = _problemsRepository.GetAll() .Where(p => p.ProblemId == problemId) .Include(p => p.Questions) .Include(p => p.Questions.Answers) .ToList(); return problems;
所以我可以看到问题,问题和答案信息。 但我的最后一个包含有一个问题,我无法弄清楚如何包含答案。
有人可以给我一些建议。
您可以使用.Select()。
var problems = _problemsRepository.GetAll() .Where(p => p.ProblemId == problemId) .Include(p => p.Questions.Select(q => q.Answers)) .ToList();
现在你的答案将被包括在内。
这在EntityFramework 7.0中已更改。
新语法将采用该forms
var problems = _problemsRepository.GetAll() .Where(p => p.ProblemId == problemId) .Include(p => p.Questions) .ThenInclude(q => q.Answers) .ToList();