用于连接的Lambda表达式

Question

public class CourseDetail
    {
        public CourseDetail();
        public string CourseId { get; set; }
        public string CourseDescription { get; set; }
        public long CourseSer { get; set; }
    }

 public class RefUIDByCourse
    {
        public long CourseSer {  get;  set; }
        public double DeliveredDose{ get; set; }
        public double PlannedDose{ get; set; }
        public string RefUID {  get;  set; }
     }
 public class RefData
    {
       public double DailyDoseLimit {  get;  set; }
       public string RefName {  get;  set; }
       public string RefUID {  get;  set; }
       public double SessionDoseLimit {  get;  set; }
    }

public class CourseSummary  
    {    
          public long CourseSer { get; set; } 
          public double DeliveredDose{ get; set; } 
          public double PlannedDose{ get; set; } 
          Public List<RefData> lstRefData {get;set;} 
    }

对于一个courseSer,RefUIDByCourse中可以有多个RefUID,对于每个RefUID,RefData中都会有一个记录

我现在有CourseDetail,RefUIDByCourse和RefData的列表,因为课程中存在课程,我必须创建CourseSummary列表.

我可以做的一件事就是为coursedetail做循环并使用linq查询获取相应的refdata并创建一个courseummary对象并将其添加到列表中.

但有没有办法通过一个linq查询来做,而不是做循环

Answer 1

加入的lambda有点涉及 - 这是一个简单的例子:

List<Person> People = new List<Person>();
List<PersonType> PeopleTypes = new List<PersonType>();

var joined = People.Join(PeopleTypes, 
  PeopleKey => PeopleKey.PersonType, 
  PeopleTypesKey => PeopleTypesKey.TypeID, 
  (Person, PersoneType) => new 
    { 
      Name = Person.Name, 
      TypeID = PersoneType.TypeID 
    });

我通常发现查询语法比lambda用于加入更具可读性

        var joined2 = from p in People
                      join pType in PeopleTypes
                      on p.PersonType equals pType.TypeID
                      where p.Name.StartsWith("whatever")
                      select new { Name = p.Name, TypeID = pType.TypeID };