我需要?jiǎng)?chuàng)建如下所示的結(jié)構(gòu)。第1節(jié)問題1消息1第2節(jié)問題2消息1消息2我編寫了下面的代碼來生成它。using System;using System.Linq;using System.Collections.Generic;public class Program{ public static void Main() { // Question collection IList<Question> QuestionList = new List<Question>() { new Question() { QuestionID = 1, QuestionName = "q1", SectionID = 1 } , new Question() { QuestionID = 2, QuestionName = "q2", SectionID = 1 } , new Question() { QuestionID = 3, QuestionName = "q3", SectionID = 2 } , new Question() { QuestionID = 4, QuestionName = "q4" , SectionID = 2 } , new Question() { QuestionID = 5, QuestionName = "q5" } }; IList<Section> SectionList = new List<Section>() { new Section(){ SectionID = 1, SectionName="Section 1"}, new Section(){ SectionID = 2, SectionName="Section 2"}, new Section(){ SectionID = 3, SectionName="Section 3"} }; IList<Messages> MessagesList = new List<Messages>() { new Messages(){ MessagesID = 1, MessagesName="Message 1",QuestionID=1}, new Messages(){ MessagesID = 2, MessagesName="Message 2",QuestionID=1}, new Messages(){ MessagesID = 3, MessagesName="Message 3",QuestionID=2} }; var groupJoin = SectionList.GroupJoin(QuestionList, //inner sequence sct => sct.SectionID, //outerKeySelector s => s.SectionID, //innerKeySelector (sct, QuestionsGroup) => new // resultSelector { Questions = QuestionsGroup, SectionName = sct.SectionName });不幸的是，我找不到加入這兩個(gè)小組的方法。因?yàn)椴糠趾蛦栴}使用sectionid連接，而問題和消息使用questionid連接。當(dāng)我使用第二組加入時(shí)，我收到錯(cuò)誤 Questionid 在這種情況下不存在。我該如何解決這個(gè)問題。
3 回答
拉風(fēng)的咖菲貓
TA貢獻(xiàn)1995條經(jīng)驗(yàn) 獲得超2個(gè)贊
您的請(qǐng)求與您的對(duì)象不匹配，您是否希望在所有部分中都有一個(gè)結(jié)合 Message 和 Question 的唯一列表？
或者，如果您想要像“Section => Questions => Messages”這樣的樹，您可以這樣做：
var group1 = SectionList.Select(section => new Section
{
SectionID = section.SectionID,
SectionName = section.SectionName,
Questions = QuestionList.Where(question => question.SectionID.Equals(section.SectionID))
.Select(question => new Question
{
QuestionID = question.QuestionID,
QuestionName = question.QuestionName,
SectionID = section.SectionID,
Messages = MessagesList.Where(message => message.QuestionID.Equals(question.QuestionID))
.Select(message => new Messages
{
MessagesID = message.MessagesID,
MessagesName = message.MessagesName,
QuestionID = message.QuestionID
})
})
});
當(dāng)然，你需要稍微改變一下你的類：
public class Question
{
public int QuestionID { get; set; }
public string QuestionName { get; set; }
public int SectionID { get; set; }
public IEnumerable<Messages> Messages { get; set; }
}
public class Section
{
public int SectionID { get; set; }
public string SectionName { get; set; }
public IEnumerable<Question> Questions { get; set; }
}
慕碼人8056858
TA貢獻(xiàn)1803條經(jīng)驗(yàn) 獲得超6個(gè)贊
您可以加入QuestionListinto MessagesList。QuestionMessagesList之后，您需要QuestionMessagesList加入SectionList。
var questionMessages = QuestionList.GroupJoin(MessagesList,
q => q.QuestionID,
m => m.QuestionID,
(Question, Messages) => new { Question, Messages }
);
var groupJoin = SectionList.GroupJoin(questionMessages,
sct => sct.SectionID,
s => s.Question.SectionID,
(sct, QuestionsGroup) => new
{
Questions = QuestionsGroup,
SectionName = sct.SectionName
});
然后：
foreach (var item in groupJoin)
{
Console.WriteLine(item.SectionName);
foreach (var stud in item.Questions)
{
Console.WriteLine($" - {stud.Question.QuestionName}");
foreach (var message in stud.Messages)
{
Console.WriteLine($" -- {message.MessagesName}");
}
}
}
繁星淼淼
TA貢獻(xiàn)1775條經(jīng)驗(yàn) 獲得超11個(gè)贊
您的創(chuàng)建結(jié)構(gòu)應(yīng)該改變，但如果您想要一個(gè)保留大部分創(chuàng)建結(jié)構(gòu)的解決方案，您可以使用這個(gè)
但請(qǐng)注意，在每個(gè)問題和每個(gè)部分中使用 where 并不利于性能。您應(yīng)該在創(chuàng)建部分列表時(shí)創(chuàng)建消息列表和問題列表。
IList<Messages> MessagesList = new List<Messages>() {
new Messages(){ MessagesID = 1, MessagesName="Message 1",QuestionID=1},
new Messages(){ MessagesID = 2, MessagesName="Message 2",QuestionID=1},
new Messages(){ MessagesID = 3, MessagesName="Message 3",QuestionID=2}
};
// Question collection
IList<Question> QuestionList = new List<Question>() {
new Question() { QuestionID = 1, QuestionName = "q1", SectionID = 1,messages = MessagesList.Where(message=> message.QuestionID==1).ToList() } ,
new Question() { QuestionID = 2, QuestionName = "q2", SectionID = 1,messages = MessagesList.Where(message=> message.QuestionID==2).ToList() } ,
new Question() { QuestionID = 3, QuestionName = "q3", SectionID = 2,messages = MessagesList.Where(message=> message.QuestionID==3).ToList() } ,
new Question() { QuestionID = 4, QuestionName = "q4" , SectionID = 2 ,messages = MessagesList.Where(message=> message.QuestionID==4).ToList()} ,
new Question() { QuestionID = 5, QuestionName = "q5" , SectionID = 2 ,messages = MessagesList.Where(message=> message.QuestionID==5).ToList() }
};
IList<Section> SectionList = new List<Section>() {
new Section(){ SectionID = 1, SectionName="Section 1",questions = QuestionList.Where(question=> question.SectionID == 1).ToList()},
new Section(){ SectionID = 2, SectionName="Section 2",questions = QuestionList.Where(question=> question.SectionID == 2).ToList()},
new Section(){ SectionID = 3, SectionName="Section 3",questions = QuestionList.Where(question=> question.SectionID == 3).ToList()}
};
foreach (var section in SectionList)
{
Console.WriteLine("Section: " + section.SectionName);
foreach (var question in section.questions)
{
Console.WriteLine("\tQuestion: " + question.QuestionName);
foreach (var message in question.messages)
{
Console.WriteLine("\t\tMessage: " + message.MessagesName);
}
}
}
為此，您必須稍微更改您的課程。
public class Question
{
public int QuestionID { get; set; }
public string QuestionName { get; set; }
public int SectionID { get; set; }
public List<Messages> messages { get; set; }
}
public class Messages
{
public int MessagesID { get; set; }
public string MessagesName { get; set; }
public int QuestionID { get; set; }
}
public class Section
{
public int SectionID { get; set; }
public string SectionName { get; set; }
public List<Question> questions { get; set; }
}
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