c#-4.0 – 性能问题：如何一次执行两个lambda表达式？使用“包含”和“任何”运算符

示例代码

var Ids = _db.Projects.Where(Project=>Project.Title!="test23rdoct")
    .Select (pro => pro.Id);

Expression<Func<Company,bool>> masterExpression = 
    Company => Company.Participants.Any(part => ids.Contains(part.Project.Id));

IQueryable<Object> queryEntity = _db.Companies.Where(masterExpression)

上面的查询执行两次.在服务器中存储ID(有时ID超过50k计数).它会导致性能问题.任何人都可以建议如何组合这两个查询并立即执行？

解决方法

怎么样：

var queryEntity = _db.Companies.Where(c => c.Partipants.Any(p => p.Project.Title != "test23rdoct"));

编辑：
使用复杂查询,您还可以拆分：

Func<Project,bool> projectFilter = Project => ((Compare(Convert(Project.Title),"a") > 0) AndAlso ((Convert(Project.Title) != "test23rdoct") AndAlso
(Project.Participants.Any(Participant => (Compare(Convert(Participant.ParticipantRole.Name),"Finance") > 0)) AndAlso 
(Project.Participants.Any(Participant => (Convert(Participant.Person.FirstName) != "test1")) AndAlso 
Project.Participants.Any(Participant => (Compare(Convert(Participant.Company.Name),"test") > 0))))));

然后做：

var queryEntity = _db.Companies.Where(c => c.Partipants.Any(p => projectFilter(p.Project));