Nested select expression give error Expression of type 'System.Func`2[X,Y]' cannot be used for parameter of type 'System.Linq.Expressions.Expression`1[System.Func`2[X,Y]]'

[Anderman]

When I tried the following code I get an runtime error. I looks that the asExpandable is not working for select

private async Task<List<SurveyEditChapter>> GetSurveyChapters(int surveyId)
        {
            return await _ctx.SurveyChapter.AsNoTracking().AsExpandable().Where(x => x.SurveyId == surveyId)
                .Select(x => new SurveyEditChapter
                {
                    SurveyChapterId = x.Id,
                    SequenceNumber = x.SequenceNumber,
                    Name = x.Name,
                    Description = x.Description,
                    Questions = x.ChapterQuestions.Select(Projector().Compile()).OrderBy(z => z.SequenceNumber).ToList()
                })
                .OrderBy(x => x.SequenceNumber).ToListAsync();
        }
        private static Expression<Func<ChapterQuestion, SurveyEditQuestion>> Projector()
        {
            return y => new SurveyEditQuestion
            {
                ChapterQuestionId = y.Id,
                QuestionId = y.Question.Id,
                Code = y.Code,
                Mandatory = y.Mandatory,
                Visible = y.Visible,
                ChartTypeFlag = y.ChartTypeFlags,
                QuestionTypeFlag = y.QuestionTypeFlags,
                SequenceNumber = y.SequenceNumber,
                Name = y.Question.Name,
                Description = y.Question.Description,
                QuestionTypeFlags = y.Question.QuestionTypeFlags,
                ChartTypeFlags = y.Question.ChartTypeFlags,
                Answers = y.Question.QuestionAnswers.Select(z => new QuestionEditAnswer
                {
                    QuestionAnswerId = z.Id,
                    Value = z.Value,
                    Description = z.AnswerText.Description,
                    ImageId = z.AnswerImage.Id
                }).ToList()
            };
        }

[kyletindle]

This has just caught me out. Did you manage to get around this issue?

[Anderman]

I didn't not use it anymore. Probably I rewrite some linq queries

[joshuajung]

In case another newbie like me ends up here with a similar issue: for me, the root cause was that I was trying to generate an expression inline, like this:

query = query
                .Where(o => o.OrderPositions.Any(HasBuildingIsAssignedToUserDirectly(userId).Compile()));

What actually worked for me instead was to split up the procedure:

var filterExpression = HasBuildingIsAssignedToUserDirectly(userId);
query = query
                .Where(o => o.OrderPositions.Any(filterExpression.Compile()));

I'm seeing something similar in the above example as well.