フォームにはセクションが 1 つしかないため、フォームのセクションのリストは表示されません。(つまり、SectionID は Form で定義され、Section では FormID ではありません)。ただし、次の Linq クエリは、指定された FormID のセクションと関連する質問を返します。
void Main()
{
var sections =
new []
{
new Section { SectionID = 1, SectionName = "SectionName1" },
new Section { SectionID = 2, SectionName = "SectionName2" }
};
var forms =
new []
{
new Form { FormID = 1, SectionID = 1 },
new Form { FormID = 2, SectionID = 1 },
new Form { FormID = 3, SectionID = 2 },
new Form { FormID = 4, SectionID = 2 }
};
var questions =
new[]
{
new Question { QuestionID = 1, Content = "Question1" },
new Question { QuestionID = 2, Content = "Question2" }
};
var sectionQuestions =
new[]
{
new SectionQuestion { SectionID = 1, QuestionID = 1 },
new SectionQuestion { SectionID = 2, QuestionID = 1 },
new SectionQuestion { SectionID = 2, QuestionID = 2 }
};
var formId = 4;
var result = forms
.Join(
sections,
f => f.SectionID,
s => s.SectionID,
(f, s) => new { Form = f, Section = s })
.Join(
sectionQuestions,
jfs => jfs.Section.SectionID,
sq => sq.SectionID,
(jfs, sq) => new { Form = jfs.Form, Section = jfs.Section, sq.QuestionID })
.Join(
questions,
jfsq => jfsq.QuestionID,
q => q.QuestionID,
(jfsq, q) => new { Form = jfsq.Form, Section = jfsq.Section, Question = q })
.Where(f => f.Form.FormID == formId)
.GroupBy(f => f.Section.SectionID)
.Select(grp => new { SectionID = grp.Key, Questions = grp.Select(g => g.Question)});
Console.WriteLine($"For Form: {formId} the following sections with their questions were found: {String.Join(", ", result.Select(r => $"SectionID: {r.SectionID}, QuestionIDs: [{String.Join(", ", r.Questions.Select(q => q.QuestionID))}]"))}");
}
public class Form
{
public Int32 FormID { get; set; }
public Int32 SectionID { get; set; }
}
public class Section
{
public Int32 SectionID { get; set; }
public String SectionName { get; set; }
}
public class SectionQuestion
{
public Int32 SectionID { get; set; }
public Int32 QuestionID { get; set; }
}
public class Question
{
public Int32 QuestionID { get; set; }
public String Content { get; set; }
}
これにより、次の結果が返されます。
フォーム: 4 の場合、質問のある次のセクションが見つかりました: SectionID: 2、QuestionIDs: [1, 2]