static void Main(string[] args)
{
List <Student> students = new List <Student>();
students.Add(new Student()
{
Id = 1, Name = "John", Grade = 7, Credits = 5
});
students.Add(new Student()
{
Id = 2, Name = "Jelly", Grade = 9, Credits = 45
});
students.Add(new Student()
{
Id = 3, Name = "Jannie", Grade = 7, Credits = 25
});
students.Add(new Student()
{
Id = 4, Name = "Jolly", Grade = 8, Credits = 15
});
IsPromotable delegatePromotable = new IsPromotable(Condition);
Student.PromoteStudent(students, delegatePromotable);
// CAN BE REDUCED INTO 1 LINE USING LAMPDA
//Student.PromoteStudent(students, s=>s.Grade > 8);
Console.ReadKey();
}
static void Main(string[] args)
{
List <Student> students = new List <Student>
{
new Student()
{
Id = 1, Name = "John", Grade = 7, Credits = 5
},
new Student()
{
Id = 2, Name = "Jelly", Grade = 9, Credits = 45
},
new Student()
{
Id = 3, Name = "Jannie", Grade = 7, Credits = 25
},
new Student()
{
Id = 4, Name = "Jolly", Grade = 8, Credits = 15
}
};
IsPromotable delegatePromotable = new IsPromotable(Condition);
Student.PromoteStudent(students, delegatePromotable);
// CAN BE REDUCED INTO 1 LINE USING LAMPDA
//Student.PromoteStudent(students, s=>s.Grade > 8);
// Invoking a normal method
var normalMethodInvokeResult = NormalMethod(2);
// Create an instance of the delegate
var normalMethodDelegate = new Manipulate(NormalMethod);
var normalResult = normalMethodDelegate(3);
// Anonymous method is a a delegate() { } and it returns a delegate
Manipulate anonymousMethodDelegate = delegate(int a) { return(a * 2); };
var anonymousResult = anonymousMethodDelegate(3);
// Lambda expressions are anything with => and a left/right value
// They can return a delegate (so a method that can be invoked)
// or an Expression of a delegate (so it can be compiled and then executed)
Manipulate lambaDelegate = a => a * 2;
var lambaResult = lambaDelegate(5);
// Nicer way to write a lamba
Manipulate nicerLambaDelegate = (a) => { return(a * 2); };
var nicerLambaResult = nicerLambaDelegate(6);
// Lamba can return an Expression
Expression <Manipulate> expressionLambda = a => a * 2;
// An Action is just a delegate with no return type and optional input
Action actionDelegate = () => { lambaDelegate(2); };
Action <int> action2Delegate = (a) => { var b = a * 2; };
// A Func is just a delegate with a return type
Func <int> myFunc = () => 2;
// Replace Manipulate with a Func
Func <int, int> funcDelegate = a => a * 2;
var funcResult = funcDelegate(5);
// Mimic the FirstOrDefault Linq expression
var items = new List <string>(new[] { "a", "b", "c", "d", "e", "f", "g" });
var itemInts = Enumerable.Range(1, 10).ToList();
// Calling the nuilt in Linq FirstOrDefault
var foundItem = items.FirstOrDefault(item => item == "c");
// Calling our version
var foundItem2 = items.GetFirstOrDefaultCustom(item => item == "c");
var foundItem3 = itemInts.GetFirstOrDefaultCustom(item => item > 4);
Console.ReadKey();
}
