Object initializer

Question

Original program is given in the following website and modified incomplete program is given below. Please help me to execuate this program. Modification is coloured.
http://www.dotnetperls.com/icomparable

using System;
using System.Collections.Generic;

class Employee : IComparable<Employee>
{
private int salary;
private string name;

public Employee(string name, int salary)//public constructor
{
this.salary = salary;
this.name = name;
}

public string getName()
{
return name;
}

public int getSalary()
{
return salary;
}

public int CompareTo(Employee other)
{
// Alphabetic sort if salary is equal. [A to Z]
if (this.salary == other.salary)
{
return this.name.CompareTo(other.name);
}
// Default to salary sort. [High to low]
return other.salary.CompareTo(this.salary);
}

public override string ToString()
{
// String representation.
return this.salary.ToString() + "," + this.name;
}
}

class Program
{
static void Main()
{
List<Employee> list = new List<Employee>();
list.Add(new Employee() { Name = "Steve", Salary = 10000 });
list.Add(new Employee() { Name = "Janet", Salary = 10000 });
list.Add(new Employee() { Name = "Andrew", Salary = 10000 });
list.Add(new Employee() { Name = "Bill", Salary = 500000 });
list.Add(new Employee() { Name = "Lucy", Salary = 8000 });

// Uses IComparable.CompareTo()
list.Sort();

// Uses Employee.ToString
foreach (var element in list)
{
Console.WriteLine(element);
}
Console.ReadKey();
}
}
/*
500000,Bill
10000,Andrew
10000,Janet
10000,Steve
8000,Lucy
*/

Maha · Answer

Thank you for your help.

Vulpes · Answer

You can do it like this. The 'salary' field is now protected from invalid input. The upper limit may be silly but it makes the point! using System; using System.Collections.Generic; class Employee : IComparable { private int salary; // added private backing field public int Salary // replaces automatic property { get { return salary; } set { if (value { Console.WriteLine(Salary can't be negative - using 0 instead); salary = 0; } else if (value > 400000) { Console.WriteLine(Nobody earns {0} in this firm - using 400000 instead value); salary = 400000; } else { salary = value; } } } public string Name { get; set; } public int CompareTo(Employee other) { // Alphabetic sort if salary is equal. [A to Z] if (this.Salary == other.Salary) { return this.Name.CompareTo(other.Name); } // Default to salary sort. [High to low] return other.Salary.CompareTo(this.Salary); } public override string ToString() { // String representation. return this.Salary.ToString() +  + this.Name; } } class Program { static void Main() { List list = new List (); list.Add(new Employee() { Name = Steve Salary = 10000 }); list.Add(new Employee() { Name = Janet Salary = 10000 }); list.Add(new Employee() { Name = Andrew Salary = 10000 }); list.Add(new Employee() { Name = Bill Salary = 500000 }); list.Add(new Employee() { Name = Lucy Salary = 8000 }); // Uses IComparable.CompareTo() list.Sort(); // Uses Employee.ToString foreach (var element in list) { Console.WriteLine(element); } } }

Maha · Answer

How can program in the above website be modified with data protection concept while keeping object initializer concept intact?

Vulpes · Answer

Maha Data protection is still possible with object initializers but you have to do it through 'ordinary' properties - you can't use methods for this purpose. In the DNP article they were using public properties though there was no possibility of data protection because the properties were 'automatic' i.e. the backing fields and code for the properties were automatically generated by the compiler.

Ken H · Answer

using System; using System.Collections.Generic; using System.Collections; namespace IComparableDemo { class Employee:IComparable { private int salary; private string name; public Employee(string name int salary) { this.salary = salary; this.name = name; } public string getName { get{return name;} } public int getSalary { get { return salary; } } int IComparable.CompareTo(object right) { if (!(right is Employee)) { throw new ArgumentException(Parameter must be for Employee.); } return name.CompareTo(((Employee)right).name); } public int CompareTo(Employee right) { return name.CompareTo(right.name); } public override string ToString() { return this.name; } /* inner class */ private static SalaryComparer _salaryComparer = null; public static IComparer _SalaryComparer { get { if (_salaryComparer == null) { _salaryComparer = new SalaryComparer(); } return _salaryComparer; } } private class SalaryComparer : IComparer { int IComparer.Compare(object left object right) { if (!(left is Employee) || !(right is Employee)) { throw new ArgumentException(Parameter must be for Employee.); } return ((Employee)left).salary.CompareTo(((Employee)right).salary); } } } class Program { static void Main(string[] args) { Employee[] emp = new Employee[5]; emp[0]=new Employee(Steve10000); emp[1]=new Employee(Janet10000); emp[2]=new Employee(Andrew10000); emp[3]=new Employee(Bill500000); emp[4]=new Employee(Lucy8000); Array.Sort(empEmployee._SalaryComparer); /* foreach (Employee i in emp) { Console.WriteLine(i.getSalary+ +i.getName); }*/ for (int i =4; i>=0; i--) { Console.WriteLine(emp[i].getSalary+ +emp[i].getName); } Console.ReadKey(); } } } // output result should is: 500000 Bill 10000 Janet 10000 Andrew 10000 Steve 8000 Lucy

Maha · Answer

So that data protection is not possible with object initializer.

Vulpes · Answer

Object initializers can only be used with the Employee class if the class has accessible properties or fields called Name and Salary. As a result of the modifications you've made it no longer has public properties with these names. I'd therefore use its constructor instead. For example: list.Add(new Employee(Bill 10000));