Question

var trainingclasses = this.trainingClassRepository.GetAllclassSession().Include(x => x.Trainer).Include(x => x.TrainingRoom).Include(x => x.Session).Where(x => x.ClassId == id);
foreach (var tclass in trainingclasses)
{
    double roomcost = trainingclasses.Select(x => x.TrainingRoom.CostPerHour).FirstOrDefault();
    double trainercost = trainingclasses.Select(x => x.Trainer.Cost).FirstOrDefault();
    double duration = trainingclasses.Select(x => x.Session.Duration).FirstOrDefault();
}

在上面的代码中，序列的第一条记录总是在提取。任何人都可以帮助这个。

Answer 1

不要在foreach中使用您的集合，而是在遍历列表，因此您可以从tclass获取数据而不是来自trainingClasses。由于您使用了FirstOrDefault

，因此仅提取了第一项

更改为此代码

foreach (var tclass in trainingclasses)
{
    double roomcost = tclass.TrainingRoom.CostPerHour;
    double trainercost = tclass.Trainer.Cost;
    double duration = tclass.Session.Duration;
}

Answer 2

不清楚，

将您的代码更改为

double roomcost = tclass.TrainingRoom.CostPerHour;

而不是

double roomcost = trainingclasses.Select(x => x.TrainingRoom.CostPerHour).FirstOrDefault();

Answer 3

调用.ToList（）来实现您的收藏

var trainingclasses = this.trainingClassRepository.GetAllclassSession().Include(x => x.Trainer).Include(x => x.TrainingRoom).Include(x => x.Session).Where(x => x.ClassId == id).ToList();

序列的第一条记录总是在提取？

3 个答案: