IList List is null in my Composition Class .. WHY? - list

Question

I am usling IList List property to get a list of students class in University class .. as i try to access this list in department Class which is a part of university class .. the List is Null .. can anyone tell the reason?
namespace UniversitySystem
{
class University : CollectionBase
{
private string _uniName;
Departments _depart = new Departments();
public University(string un, string dn, string cp, List<Student> Slist)
{
this._uniName = un;
this.CED.DepartName = dn;
this.CED.ChairPerson = cp;
foreach (Student s in Slist)
{
List.Add(s);
}
}
#region properties
public string UniName
{
get { return _uniName; }
set { _uniName = value; }
}
public Departments CED
{
get { return _depart; }
set { _depart = value; }
}
#endregion
public class Departments : CollectionBase
{
private string _departName;
public string DepartName
{
get { return _departName; }
set { _departName = value; }
}
private string _chairPerson;
public string ChairPerson
{
get { return _chairPerson; }
set { _chairPerson = value; }
}
public List<Student> StudentListForCED = new List<Student>();
public Departments()
{
_departName = null;
_chairPerson = null;
StudentListForCED = null;
}
public Departments(string dn, string cp, List<Student> Slist)
{
this._departName = dn;
this._chairPerson = cp;
foreach (Student s in Slist)
{
List.Add(s);
}
}
public void showDetails()
{
Console.WriteLine("Departmental Info");
Console.WriteLine("DepartmentName: " + _departName);
Console.WriteLine("Chairperson Name: " + _chairPerson);
Console.WriteLine("Student Info:");
foreach (Student item in List)
{
Console.WriteLine("Name: " + item.Name);
Console.WriteLine("deptName: " + item.RegNo);
Console.WriteLine("total marks: " + item.TotalMarksObtained);
Console.WriteLine("percentage: " + item.GetPercentage());
}
}
}
}
}
THE main() part is
namespace UniversitySystem
{
class Program
{
static void Main(string[] args)
{
List<Student> slist = new List<Student>();
slist.Add(new Student("sana", 1234, "CIS", 650));
slist.Add(new Student("anam", 2345, "BCIT", 400));
slist.Add(new Student("fizzza", 2670, "Electrical", 670));
University u1 = new University("NED", "computer", "UKP", slist);
Console.WriteLine(u1.CED.DepartName);
u1.CED.showDetails();
}
}
}

Answer 1

The initializing code for University does not store the list you give it as a parameter.
try storing the list in a variable in either the department or the university object itself, and when you are showing the details for either of those object you can reference that list, the one you stored upon creating the object.
Hope that helps!

Answer 2

I made a couple changes that should work.
public Departments(string dn, string cp, List<Student> Slist)
{
this._departName = dn;
this._chairPerson = cp;
foreach (Student s in Slist)
{
StudentListForCED.Add(s);
}
}
public void showDetails()
{
Console.WriteLine("Departmental Info");
Console.WriteLine("DepartmentName: " + _departName);
Console.WriteLine("Chairperson Name: " + _chairPerson);
Console.WriteLine("Student Info:");
foreach (Student item in StudentListForCED)
{
Console.WriteLine("Name: " + item.Name);
Console.WriteLine("deptName: " + item.RegNo);
Console.WriteLine("total marks: " + item.TotalMarksObtained);
Console.WriteLine("percentage: " + item.GetPercentage());
}
}
Please read this a little more thoroughly.