public static void IsPromotable(List <Employee> emp, IsEligibleforPromotion IsEligible) // Pass the delegate as parameter which references the logic method which finds eligible/not
{
if (emp != null)
{
foreach (Employee employee in emp)
{
// if (emp.YearsOfExp > 5) // Hard coded logic inside a class , if at all anytime consumer (who uses this class) needs a logic change will be under trouble.
if (IsEligible(employee)) // calling the method delegate
{
Console.WriteLine("Eligible");
}
else
{
Console.WriteLine("Not Eligible");
}
}
}
else
{
Console.WriteLine("Employee List is Empty");
}
}
static void Main(string[] args)
{
Sample s = new Sample();
//Instantiating the delegates
Addnumbers Add = new Addnumbers(s.Addnum); //constructor clearly shows the signature of the target method to be given, if there are any discrepancy , it will throw compile error
// shows its type safety
SayHello Say = new SayHello(s.SayHello); // if i try to give Addnum method here (int method), immediately shows error.
//IsEligibleforPromotion IsEligible = emp => emp.Salary >= 10000; // Delegate instantiation
IsEligibleforPromotion IsEligible = new IsEligibleforPromotion(Program.IsEligibleforPromote); // Delegate instantiation
List <Employee> emplist = new List <Employee>(); // To understand the delegate usage, how to make resuable code logic
emplist.Add(new Employee {
Name = "Mike", Salary = 1000, YearsOfExp = 4
});
emplist.Add(new Employee {
Name = "Mary", Salary = 11000, YearsOfExp = 5
});
emplist.Add(new Employee {
Name = "Matt", Salary = 10000, YearsOfExp = 6
});
emplist.Add(new Employee {
Name = "John", Salary = 8000, YearsOfExp = 5
});
//Calling the methods via Delegates
Console.WriteLine(Add.Invoke(10, 150)); // Even this way/below way we can call the methods via Delegates.
Console.WriteLine(Add(10, 250));
Console.WriteLine(Say("Gowthaman"));
Employee.IsPromotable(emplist, IsEligible); // Calling the Method of consumed class which is out of our control
Console.ReadLine();
}