Question

我是LINQ的新手。我有一个这样的课：

public class StudentResults
{

    public int Id { get; set; }

    public ResultsStatus StatusResult { get; set; }

    public string Message { get; set; }

    public StudentDetails Detail { get; set; }

}

有一种方法可以将上述类的List返回给变量

我需要通过该变量进行迭代，并将学生分成两个不同的类。 PassedStudents，FailedStudents基于ResultsStatus。

这是我尝试过的但它不起作用

 var studIds = from r in StudList
 group r by r.Id into GroupedData
  select new 
  {
   //what to put here
  };
  foreach(var crs in studIds)
  {
   //what to put here to get all student names from the Detail property.
  }

还有其他办法吗？

Answer 1

就个人而言，我只想将其视为两个问题：

var passed = StudList.Where(student => student.StatusResult == ResultStatus.Passed);
var failed = StudList.Where(student => student.StatusResult == ResultStatus.Failed);

Console.WriteLine("Passed...");
foreach(var student in passed)
   Console.WriteLine(student.Detail.Name);

Console.WriteLine("Failed...");
foreach(var student in failed)
   Console.WriteLine(student.Detail.Name);

Answer 2

听起来你喜欢2个列表：一个用于失败，一个用于传递。

试试这个：

List<StudentResults> failed = StudList.Where(x=>x.ResultStatus=="Failed")
                                      .ToList();

List<StudentResults> passed = StudList.Where(x=>x.ResultStatus=="Passed")
                                      .ToList();

Answer 3

只需使用“where”。例如，要获得所有“PassedStudents”：

var passedStudents = from student in StudentList
                     where student.StatusResult == ResultsStatus.PassedStudent
                     select student;

foreach (var student in passedStudents)
{
    Console.WriteLine("[{0}.] {1} passed.", student.Id, student.Detail.Name);
}

您也可以使用lambda表达式编写查询：

var passedStudents = 
    StudentList.Where(student => student.StatusResult == ResultsStatus.PassedStudent);

LINQ-根据特定值排序对象列表

3 个答案: