Sorting Collections of Objects within another collection of Objects

Question

First I have 2 classes

class Student
{
    int StudentID
    string Name
    Fee fee
}
class Fees
{
    int FeeID
    string FeeName
    DateTime FeeDueDate
}

let say there are 10 students objects Student[] stud = new Student[10]

and if stud[0] has 4 fees ( Fee[4] ) and they are

FeeID=1, FeeName="Books", FeeDueDate="2014/06/25"
FeeID=2, FeeName="Tuition", FeeDueDate="2013/03/21"
FeeID=3, FeeName="Sports Equipment", FeeDueDate="2013/03/18"
FeeID=4, FeeName="School Dorm", FeeDueDate="2013/07/26"

while stud[1] has 2 fees ( Fee[2] ) and they are

FeeID=2, FeeName="Books", FeeDueDate="2014/06/20"
FeeID=4, FeeName="School Dorm", FeeDueDate="2013/03/26"

and stud[2] has ......

I need the sort the second collection which is the Fee by FeeDueDate asscending while Keep the same order of student

so after sorting would be

stud[0] =>

FeeID=3, FeeName="Sports Equipment", FeeDueDate="2013/03/18"
FeeID=2, FeeName="Tuition", FeeDueDate="2013/03/21"
FeeID=4, FeeName="School Dorm", FeeDueDate="2013/07/26"
FeeID=1, FeeName="Books", FeeDueDate="2014/06/25"

stud[1] =>

FeeID=4, FeeName="School Dorm", FeeDueDate="2013/03/26"
FeeID=2, FeeName="Books", FeeDueDate="2014/06/20"

How can this be done? Thanks

Also this image shows my collections of objects http://oi50.tinypic.com/wuq9o3.jpg

Does each student have a collection of Fees's? Also What have you tried? — Ryan Gates
– Ryan Gates, Commented Mar 12, 2013 at 21:32
that completely depends, how your field fee is implemented in your first class. it is a list, is it a database object? — user287107
– user287107, Commented Mar 12, 2013 at 21:33
i tried: objStudentWithFeeData = objStudentWithFeeData.OrderBy(stu => stu.Fees.DueDate).ToList(); but it seems it cant find the DueDate in stu.Fees The Student/Fee class is implemented on the WCF service end. I have no access to it — user1618180
– user1618180, Commented Mar 12, 2013 at 21:47
actually you shouldnt get your schoolwork done by asking on stackoverflow no matter how tempting ... — Ingo
– Ingo, Commented Mar 12, 2013 at 21:59

Jens Kloster · Accepted Answer · 2013-03-12 21:49:24Z

2

Assuming that you classes look like this:

   public class Student
    {
        public int StudentID { get; set;}
        public string Name { get; set;}
        public List<Fee> Fees {get;set;}
    }

    public class Fee
    {
        public int FeeID { get; set;}
        public string FeeName { get; set;}
        public DateTime FeeDueDate { get; set; }
    }

You could do it like this:

        Student[] studs = new Student[10]

        //somehow fill the array

        foreach (var student in studs)
        {
            student.Fees = student.Fees.OrderBy(c => c.FeeDueDate).ToList()
        }

EDIT To make sure the the Fees list is not null, you could initialize it like this:

   public class Student
   {
       public Student()
       {
         Fees = new List<Fees>();
       }

        public int StudentID { get; set;}
        public string Name { get; set;}
        public List<Fee> Fees {get;set;}
    }

edited Mar 12, 2013 at 21:49

answered Mar 12, 2013 at 21:39

Jens Kloster

11.3k5 gold badges44 silver badges55 bronze badges

Sign up to request clarification or add additional context in comments.

10 Comments

user1618180 Over a year ago

Thanks for your time, I tried your way but there is an error with student.Fees.OrderByDescending(c => c.DueDate).ToList(); Cannot implicitly convert type 'System.Collections.Generic.List<StudentList.RServiceReference.Fee>' to 'StudentList.RServiceReference.Fee[]

Jens Kloster Over a year ago

@user1618180 I have updated the answer - it should not be OrderBy Desending, just OrderBy. Check that a studens list of Fees is not null. you cound init. it in the Stundent constructor. See edit

bas Over a year ago

Lol, always nice to alt-tab back and see the EXACT SAME solution :). +1 nonetheless :)

user1618180 Over a year ago

Sorry, still given me error Cannot implicitly convert type 'System.Collections.Generic.List<StudentList.RServiceReference.Fee>' to 'StudentList.RServiceReference.Fee[]'

user1618180 Over a year ago

thanks Jens!!!! Had trouble with this school assignment. Already spent 2 hours on it

|

Ingo · Accepted Answer · 2013-03-12 22:20:35Z

Well, this would solve your 2nd Problem. Try hard to understand it... or your teacher will know the answer is not your own...

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            var students = new[] {
                new Student()   
                    { StudentID = 0, Name = "Mark", fees =
                        new List<Fee>() {
                            new Fee() { FeeID=1, FeeName="Books", FeeDueDate=new DateTime(2014,06,25), FeeAmount = 1.30 },
                            new Fee() { FeeID=2, FeeName="Tuition", FeeDueDate=new DateTime(2013,03,21), FeeAmount = .30 },
                            new Fee() { FeeID=3, FeeName="Sports Equipment", FeeDueDate=new DateTime(2013,03,18), FeeAmount = .80 },
                            new Fee() { FeeID=4, FeeName="School Dorm", FeeDueDate=new DateTime(2013,07,26), FeeAmount = 0}
                        }
                    },
                new Student()
                    { StudentID = 1, Name = "Tom", fees =
                        new List<Fee>() {
                            new Fee() { FeeID=2, FeeName="Books", FeeDueDate=new DateTime(2014,06,20), FeeAmount = 1.50 },
                            new Fee() { FeeID=4, FeeName="School Dorm", FeeDueDate=new DateTime(2013,03,26), FeeAmount = 4.00 }
                        }
                    }
                };

            var sorted = (from student in students
                         select new
                         {
                             stud = student.StudentID,
                             name = student.Name,
                             feesum = student.fees.Sum(x => x.FeeAmount),
                             fees =
                                 from fee in student.fees
                                 orderby fee.FeeDueDate ascending
                                 select fee
                         }).OrderByDescending(s => s.feesum);

            foreach (var item in sorted)
            {
                Console.WriteLine("stud[{0}] => {1}, Fees: {2}", item.stud, item.name, item.feesum);
                foreach (var f in item.fees)
                {
                    Console.WriteLine(f.ToString());
                }
                Console.WriteLine();
            }
        }
    }


    public class Student
    {
        public int StudentID {get; set;}
        public string Name {get; set;}
        public List<Fee> fees {get; set;}
    }

    public class Fee
    {
        public int FeeID {get; set;}
        public string FeeName {get; set;}
        public DateTime FeeDueDate { get; set; }
        public double FeeAmount { get; set; }

        public override string ToString()
        {
             return String.Format("FeeID={0,2}, FeeName={1,20}, FeeDueDate={2}", FeeID, FeeName, FeeDueDate);
        }
    }
}

Ingo · Accepted Answer · 2013-03-12 21:53:39Z

1

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            var students = new[] {
                new Student()   
                    { StudentID = 0, Name = "Mark", fees =
                        new List<Fee>() {
                            new Fee() { FeeID=1, FeeName="Books", FeeDueDate=new DateTime(2014,06,25) },
                            new Fee() { FeeID=2, FeeName="Tuition", FeeDueDate=new DateTime(2013,03,21) },
                            new Fee() { FeeID=3, FeeName="Sports Equipment", FeeDueDate=new DateTime(2013,03,18) },
                            new Fee() { FeeID=4, FeeName="School Dorm", FeeDueDate=new DateTime(2013,07,26)}
                        }
                    },
                new Student()
                    { StudentID = 1, Name = "Tom", fees =
                        new List<Fee>() {
                            new Fee() { FeeID=2, FeeName="Books", FeeDueDate=new DateTime(2014,06,20) },
                            new Fee() { FeeID=4, FeeName="School Dorm", FeeDueDate=new DateTime(2013,03,26) }
                        }
                    }
                };

            var sorted = from student in students
                         orderby student.StudentID
                         select new
                         {
                             stud = student.StudentID,
                             fees =
                                 from fee in student.fees
                                 orderby fee.FeeDueDate ascending
                                 select fee
                         };

            foreach (var item in sorted)
            {
                Console.WriteLine("stud[{0}] => ", item.stud);
                foreach (var f in item.fees)
                {
                    Console.WriteLine(f.ToString());
                }
                Console.WriteLine();
            }
        }
    }


    public class Student
    {
        public int StudentID {get; set;}
        public string Name {get; set;}
        public List<Fee> fees {get; set;}
    }

    public class Fee
    {
        public int FeeID {get; set;}
        public string FeeName {get; set;}
        public DateTime FeeDueDate { get; set; }

        public override string ToString()
        {
             return String.Format("FeeID={0,2}, FeeName={1,20}, FeeDueDate={2}", FeeID, FeeName, FeeDueDate);
        }
    }
}

answered Mar 12, 2013 at 21:53

Ingo

1,81518 silver badges32 bronze badges

4 Comments

Ingo Over a year ago

well its a copy of my whole Program.cs of a console app. As always I seem to be too slow :-) have fun anyway

user1618180 Over a year ago

Thanks Ingo!, stackoverflow is full of awesome knowledgable people

user1618180 Over a year ago

let say in the Fee has another property, FeeAmount now I need to sort again by student with highest amount of FeeAmount my email is [email protected] maybe we can have conversation there

Ingo Over a year ago

just replace orderby fee.FeeDueDate ascending by orderby fee.FeeAmount ascending ... if you want to create a method where you can pass the property Name after which the sorting shall be done, I would probably use a linq Expression like Jens did, and pass the property as a Lambda to the method so inside the method you can place the Lambda as you got it into the linq expressions .OrderBy( Lambda ). .. oh and then you would Need to Aggregate the sum of the amount field to the student

Collectives™ on Stack Overflow

Sorting Collections of Objects within another collection of Objects

3 Answers 3

10 Comments

Comments

4 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

3 Answers 3

10 Comments

Comments

4 Comments

Your Answer

Sign up or log in

Post as a guest

Related