如何使用 C# 使用 LINQ 从 GenericList<T> 创建 XML 文件 [关闭]

Question

class Program
{
    class Student
    {
        public int SID { get; set; }
        public string Name { get; set; }
        public string Major { get; set; }
        public List<SubjGrade> SubjectGrades { get; set; }
    }

class SubjGrade
{
    public string Subject { get; set; }
    public decimal grade { get; set; }
}

static List<Customer> LoadCustomers(string file) {}

static void Main(string[] args)
{
    var Students = LoadStudents(@"C:\Users\Chris\Documents\Students.txt");

    var studXML = 
        new XElement("Root",
                        from student in Students 
                        select new XElement("Student",
                                    new XElement("SID",student.SID),
                                    new XElement("Name",student.Name),
                                    new XElement("Major",student.Major)
                        // ????
                        // I cannot figure out how to create XElements
                        // for the SubjGrade list
                                            ) // end student
                    ); // end root
    Console.WriteLine(studXML);


    // this test works just fine but not what i am trying achive
    IEnumerable<Student> studs = from student in Students select student;
    foreach (var s in studs)
    {
        Console.WriteLine("{0} {1}\t{2}", 
                s.SID.ToString(), s.Name, s.Major);
        Console.WriteLine("Class Cnt: {0}", 
                s.SubjectGrades.Count.ToString());
        foreach (var g in s.SubjectGrades)
        {
            Console.WriteLine("\t{0}\t{1}", 
                    g.Subject, g.grade.ToString());        
        }
    }
}

Answer 1

这将允许您在 Student 元素下方创建多个 Grade 元素。

var studXML =
            new XElement("Root",
                            from student in Students
                            select new XElement("Student",
                                        new XElement("SID", student.SID),
                                        new XElement("Name", student.Name),
                                        new XElement("Major", student.Major),
                                        new XElement("Grades",
                                                    from subjectGrade in student.SubjectGrades
                                                    select new XElement("Grade",
                                                               new XElement("Subject", subjectGrade.Subject),
                                                               new XElement("Grade", subjectGrade.grade)))
                                                ) // end student
                        ); // end root
        Console.WriteLine(studXML);

请注意，这并不能防止 SubjectGrades 为空。