C# 复杂linq编译查询

我试图弄明白如何将这样一个复杂的查询转换为编译后的查询，并保持代码干净。这个没有那么复杂，但它是一个例子，我有更复杂的查询

因此，我想转换这个预测查询：

public List<GetAnswers> GetAnswers(int pQuestionId, string pSearch,   int?       pSkip, int? pTake, GetAnswersOrderBy pOrderBy, bool  pOrderByIsAscending, out int pTotalNumberOfLines)
{
    string search = pSearch.ToUpper().Replace(" ", "");
    string languageCode = Thread.CurrentThread.CurrentCulture.ToString().ToLower().Substring(0, 2);
    IQueryable<Answer> query = this.Context.Set<Answer>();
    //Filter question by questionnaire
    query = query.Where(w => w.QuestionID == pQuestionId);

    if (!string.IsNullOrEmpty(pSearch))
        query = query.Where(w => (w.AnswerTranslations.Any(a => languageCode == a.LanguageCode)
                         ? w.AnswerTranslations.FirstOrDefault(a => languageCode == a.LanguageCode).Label
                         : w.AnswerTranslations.OrderBy(o => o.Language.Priority).FirstOrDefault().Label)
                         .ToUpper().Replace(" ", "")
                         .Contains(search));
    switch (pOrderBy)
    {
        case GetAnswersOrderBy.CorrectAnswer:
            query = pOrderByIsAscending ? query.OrderBy(w => w.CorrectAnswer) : query.OrderByDescending(w => w.CorrectAnswer);
            break;
        case GetAnswersOrderBy.ResponseCount:
            query = pOrderByIsAscending ? query.OrderBy(w => w.ResponseCount) : query.OrderByDescending(w => w.ResponseCount);
            break;
        default:
            break;
    }
    pTotalNumberOfLines = query.Count();

    var pagedQuery = query.Skip(pSkip ?? 0)
                         .Take(pTake ?? pTotalNumberOfLines);
    var projectedQuery = pagedQuery.Select(s =>
        new
        {
            Answer = s,
            s.AnswerTranslations,
            AnswerTranslationsLanguages = s.AnswerTranslations.Select(qt => qt.Language),
        }).ToList();
    return projectedQuery.Select(s => new GetAnswers()
    {
        Id = s.Answer.Id,
        Label = s.Answer.Label,
        CorrectAnswer = s.Answer.CorrectAnswer,
        Feedback = s.Answer.Feedback,
        Weighting = s.Answer.Weighting
    }).ToList();
}

public List GetAnswers（int pQuestionId，string pSearch，int？pSkip，int？pTake，GetAnswersOrderBy pOrderBy，bool porderbyisasceding，out int pTotalNumberOfLines）
{
字符串搜索=pSearch.ToUpper（）.Replace（“，”）；
string languageCode=Thread.CurrentThread.CurrentCulture.ToString（）.ToLower（）.Substring（0,2）；
IQueryable query=this.Context.Set（）；
//通过问卷筛选问题
query=query.Where（w=>w.QuestionID==pQuestionId）；
如果（！string.IsNullOrEmpty（pSearch））
query=query.Where（w=>（w.AnswerTranslations.Any）（a=>languageCode==a.languageCode）
？w.AnswerTranslations.FirstOrDefault（a=>languageCode==a.languageCode）.Label
：w.AnswerTranslations.OrderBy（o=>o.Language.Priority.FirstOrDefault（）.Label）
.ToUpper（）.Replace（“，”）
。包含（搜索））；
开关（pOrderBy）
{
case GetAnswersOrderBy.correct答案：
query=pOrderByIsAscending？query.OrderBy（w=>w.CorrectAnswer）：query.OrderByDescending（w=>w.CorrectAnswer）；
打破
案例GetAnswersOrderBy.ResponseCount：
query=pOrderByIsAscending？query.OrderBy（w=>w.ResponseCount）：query.OrderByDescending（w=>w.ResponseCount）；
打破
违约：
打破
}
pTotalNumberOfLines=query.Count（）；
var pagedQuery=query.Skip（pSkip±0）
.取（pTake？？pTotalNumberOfLines）；
var projectedQuery=pagedQuery.Select（s=>
新的
{
答案=s，
s、 答:，
AnswerTranslationLanguages=s.AnswerTranslations.Select（qt=>qt.Language），
}).ToList（）；
返回projectedQuery.Select（s=>newgetanswers（）
{
Id=s.Answer.Id，
Label=s.Answer.Label，
CorrectAnswer=s.Answer.CorrectAnswer，
反馈=s.答案.反馈，
权重=s.答案
}).ToList（）；
}

要保持代码整洁，请执行以下操作：

public List<Answer> GetAnswers(int pQuestionId, string pSearch,   int?       pSkip, int? pTake, GetAnswersOrderBy pOrderBy, bool  pOrderByIsAscending, out int pTotalNumberOfLines)
{
    var compiledQuery = CompiledGetAnswers(params...);

    var projectedQuery = compiledQuery .Select(s =>
        new
        {
            Answer = s,
            s.AnswerTranslations,
            AnswerTranslationsLanguages = s.AnswerTranslations.Select(qt => qt.Language),
        }).ToList();

    return projectedQuery.Select(s => new GetAnswers()
    {
        Id = s.Answer.Id,
        Label = s.Answer.Label,
        CorrectAnswer = s.Answer.CorrectAnswer,
        Feedback = s.Answer.Feedback,
        Weighting = s.Answer.Weighting
    }).ToList();
} 

public static Func<AppDbContext, Answer, IQueryable<Answer>> CompiledGetAnswers(int pQuestionId, string pSearch,   int?       pSkip, int? pTake, GetAnswersOrderBy pOrderBy, bool  pOrderByIsAscending, out int pTotalNumberOfLines)
{
    string search = pSearch.ToUpper().Replace(" ", "");
    string languageCode = Thread.CurrentThread.CurrentCulture.ToString().ToLower().Substring(0, 2);
    IQueryable<Answer> query = this.Context.Set<Answer>();
    //Filter question by questionnaire
    query = query.Where(w => w.QuestionID == pQuestionId);

    if (!string.IsNullOrEmpty(pSearch))
        query = query.Where(w => (w.AnswerTranslations.Any(a => languageCode == a.LanguageCode)
                         ? w.AnswerTranslations.FirstOrDefault(a => languageCode == a.LanguageCode).Label
                         : w.AnswerTranslations.OrderBy(o => o.Language.Priority).FirstOrDefault().Label)
                         .ToUpper().Replace(" ", "")
                         .Contains(search));
    switch (pOrderBy)
    {
        case GetAnswersOrderBy.CorrectAnswer:
            query = pOrderByIsAscending ? query.OrderBy(w => w.CorrectAnswer) : query.OrderByDescending(w => w.CorrectAnswer);
            break;
        case GetAnswersOrderBy.ResponseCount:
            query = pOrderByIsAscending ? query.OrderBy(w => w.ResponseCount) : query.OrderByDescending(w => w.ResponseCount);
            break;
        default:
            break;
    }
    pTotalNumberOfLines = query.Count();

    var pagedQuery = query.Skip(pSkip ?? 0)
                         .Take(pTake ?? pTotalNumberOfLines);
    return CompiledQuery(AppDbContext db, Answer a) => pagedQuery;
}

public List GetAnswers（int pQuestionId，string pSearch，int？pSkip，int？pTake，GetAnswersOrderBy pOrderBy，bool porderbyisasceding，out int pTotalNumberOfLines）
{
var compiledQuery=CompiledGetAnswers（参数…）；
var projectedQuery=compiledQuery.Select（s=>
新的
{
答案=s，
s、 答:，
AnswerTranslationLanguages=s.AnswerTranslations.Select（qt=>qt.Language），
}).ToList（）；
返回projectedQuery.Select（s=>newgetanswers（）
{
Id=s.Answer.Id，
Label=s.Answer.Label，
CorrectAnswer=s.Answer.CorrectAnswer，
反馈=s.答案.反馈，
权重=s.答案
}).ToList（）；
} 
公共静态函数编译的etanswers（int pQuestionId、字符串pSearch、int？pSkip、int？pTake、GetAnswersOrderBy pOrderBy、bool porderbyisasceding、out int pTotalNumberOfLines）
{
字符串搜索=pSearch.ToUpper（）.Replace（“，”）；
string languageCode=Thread.CurrentThread.CurrentCulture.ToString（）.ToLower（）.Substring（0,2）；
IQueryable query=this.Context.Set（）；
//通过问卷筛选问题
query=query.Where（w=>w.QuestionID==pQuestionId）；
如果（！string.IsNullOrEmpty（pSearch））
query=query.Where（w=>（w.AnswerTranslations.Any）（a=>languageCode==a.languageCode）
？w.AnswerTranslations.FirstOrDefault（a=>languageCode==a.languageCode）.Label
：w.AnswerTranslations.OrderBy（o=>o.Language.Priority.FirstOrDefault（）.Label）
.ToUpper（）.Replace（“，”）
。包含（搜索））；
开关（pOrderBy）
{
case GetAnswersOrderBy.correct答案：
query=pOrderByIsAscending？query.OrderBy（w=>w.CorrectAnswer）：query.OrderByDescending（w=>w.CorrectAnswer）；
打破
案例GetAnswersOrderBy.ResponseCount：
query=pOrderByIsAscending？query.OrderBy（w=>w.ResponseCount）：query.OrderByDescending（w=>w.ResponseCount）；
打破
违约：
打破
}
pTotalNumberOfLines=query.Count（）；
var pagedQuery=query.Skip（pSkip±0）
.取（pTake？？pTotalNumberOfLines）；
返回CompiledQuery（AppDbContext数据库，答案a）=>pagedQuery；
}

我想你所说的“干净”是指“更具可读性”。你真的在这么做。我的建议是将复杂的查询放入一个方法中，并给它一个有意义的名称

例如，如果人们不查看您的查询，他们就不会理解您在下面的代码中做什么

query = query.Where(w => (w.AnswerTranslations.Any(a => languageCode == a.LanguageCode)
                         ? w.AnswerTranslations.FirstOrDefault(a => languageCode == a.LanguageCode).Label
                         : w.AnswerTranslations.OrderBy(o => o.Language.Priority).FirstOrDefault().Label)
                         .ToUpper().Replace(" ", "")
                         .Contains(search));

您可以创建一个扩展类

public static class MyQueryExtension
{
    public static IQueryable<Answer> SearchAnswersByLanguageCode(this IQueryable<Answer> query, string languageCode, string search)
    { 
        return query.Where(w => (w.AnswerTranslations.Any(a => languageCode == a.LanguageCode)
                     ? w.AnswerTranslations.FirstOrDefault(a => languageCode == a.LanguageCode).Label
                     : w.AnswerTranslations.OrderBy(o => o.Language.Priority).FirstOrDefault().Label)
                     .ToUpper().Replace(" ", "")
                         .Contains(search))
    }
}

然后，您就能够使主方法变得清晰易读

public static Func<AppDbContext, Answer, IQueryable<Answer>> CompiledGetAnswers(int pQuestionId, string pSearch,   int?       pSkip, int? pTake, GetAnswersOrderBy pOrderBy, bool  pOrderByIsAscending, out int pTotalNumberOfLines)
{
    //Do something
    if (!string.IsNullOrEmpty(pSearch))
        query = query.SearchAnswersByLanguageCode(languageCode, search);

    query = query.GetItOrdered(parameters);

    //Do something
}

public static Func CompiledGetAnswers（int pQuestionId，string pSearch，int？pSkip，int？pTake，GetAnswersOrderBy pOrderBy，bool porderbyisassending，out int pTotalNumberOfLines）
{
//做点什么
如果（！string.IsNullOrEmpty（pSearch））
query=query.SearchAnswersByLanguageCode（语言代码，搜索）；
query=query.GetItOrdered（参数）；
//做点什么
}

你已经差不多做到了。

public static Func<AppDbContext, Answer, IQueryable<Answer>> CompiledGetAnswers(int pQuestionId, string pSearch,   int?       pSkip, int? pTake, GetAnswersOrderBy pOrderBy, bool  pOrderByIsAscending, out int pTotalNumberOfLines)
{
    //Do something
    if (!string.IsNullOrEmpty(pSearch))
        query = query.SearchAnswersByLanguageCode(languageCode, search);

    query = query.GetItOrdered(parameters);

    //Do something
}