static void Main(string[] args)
{
Console.WriteLine("Hello Del20200327c!");
(int a, int b) = GetInput();
Console.WriteLine("=======using a method call=========");
int result = Add(a, b);
Console.WriteLine(result);
result = Sub(a, b);
Console.WriteLine(result);
result = Prod(a, b);
Console.WriteLine(result);
result = Mod(a, b);
Console.WriteLine(result);
result = Pow(a, b);
Console.WriteLine(result);
Console.WriteLine("=======using a delegate=========");
IntDel idel = new IntDel(Add);
Console.WriteLine(idel(a, b));
idel = Sub;
Console.WriteLine(idel(a, b));
idel = Prod;
Console.WriteLine(idel(a, b));
idel = Mod;
Console.WriteLine(idel(a, b));
idel = Pow;
Console.WriteLine(idel(a, b));
}
static void Main(string[] args)
{
// Inicialização e chamada (invoke) do delegate
//IntDel del = new IntDel(Add); // Explicitamente como qualquer objeto
IntDel del = Add; // implicitamente
//int result = del.Invoke(1, 2); // chamada explicita
int result = del(1, 2); //implicita
Console.WriteLine("Resultado: {0}", result);
}
static void Main(string[] args)
{
// Write code in Main that initializes and invokes the delegate
//IntDel del = new IntDel(Add); // Explicit del init
IntDel del = Add;
//int result = del.Invoke(1, 2); // Explicit invocation
int result = del(1, 2);
Console.WriteLine("Add result: {0}", result);
}
static void Main(string[] args)
{
//Write code in Main that initializes and invokes the delegate
//var del = new IntDel(Add);//Optional
IntDel del = Add;
//Invoke the delegate
//int result = del(1, 2);//Optional
int result = del.Invoke(1, 2);
Console.WriteLine("Add Result: {0}", result);
Console.ReadLine();
}
static void Main(string[] args)
{
WuDel_Class wuDel_Class = new WuDel_Class();
//调用无参数的委托
WuDel wuDel = wuDel_Class.Print1;
wuDel += wuDel_Class.Print2;
wuDel += wuDel_Class.Print1;//现在，委托的方法列表中有3个方法
Console.WriteLine("无参委托：");
if (null != wuDel)
{
wuDel();
}
else
{
Console.WriteLine("委托为空");
}
IntDel_Class intDel_Class = new IntDel_Class();
//调用有返回值的委托
IntDel intDel = intDel_Class.Add2;
intDel += intDel_Class.Add3;
intDel += intDel_Class.Add2;
Console.WriteLine("带返回值委托：");
Console.WriteLine("Value:{0}", intDel());
RefDel_Class refDel_Class = new RefDel_Class();
//带引用参数的委托
RefDel refDel = refDel_Class.Add2;
refDel += refDel_Class.Add3;
refDel += refDel_Class.Add2;
int Intvalue = 5;
refDel(ref Intvalue);//调用
Console.WriteLine("带引用参数的委托：");
Console.WriteLine("Value:{0}", Intvalue.ToString());
Console.ReadKey();
}
private static void Main(string[] args)
{
// WRITE CODE IN MAIN THAT INITIALIZES AND INVOKES THE DELEGATE
var delA = new IntDel(Add);
IntDel delB = Add;
// INVOKE THE DELEGATE
int resultA1 = delA.Invoke(1, 2);
int resultA2 = delB.Invoke(2, 3);
// QUERIES!!!
// Standard Query
IEnumerable <int> highScoresQuery = // Query Variable
from number in d.users // Required
where number.Fav > 50 // Optional
orderby number.Fav descending // Optional
select number.Fav; // Must end in Select or Groupby
// Projection - Int to a String
IEnumerable <string> highScoresQuery2 =
from number in d.users
where number.Fav > 80
orderby number.Fav descending
select $"The score is {number}";
// Count Expression
int highScoreCount =
(from number in d.users
where number.Fav > 80
select number.Fav)
.Count();
/********* OR ***********/
IEnumerable <int> highScoresQuery3 =
from number in d.users
where number.Fav > 80
select number.Fav;
int scoreCount = highScoresQuery3.Count();
// Groupby
var queryNumberGroup =
(from number in d.users
group number by number.Fav >= 75);
// Projection - Anonnymous Type
var favNumQuery =
from user in d.users
select new { name = user.F_name + " " + user.L_name, number = user.Fav };
// averageQuery is an IEnumerable<IGrouping<int, User>>
var averageQuery =
from user in d.users
let tenth = (int)user.Fav / 10
group user by tenth into userGrouped
orderby userGrouped.Key descending
where userGrouped.Key > 5
select userGrouped;
// Filtering using Where clause
var rangeFavs =
from user in d.users
where user.Fav > 50 && user.Fav < 80
select new { name = user.F_name + " " + user.L_name, favNum = user.Fav };
// Orderby Clause
IEnumerable <User> userQuery =
from user in d.users
orderby user.F_name, user.L_name descending
select user;
// Join Clause
var favFimlQuery =
from user in d.users
join film in d.films on user.Fav equals film.FilmID
orderby user.F_name, user.L_name
select new { user = user.F_name + " " + user.L_name, film.FilmTitle };
// Let Clause
string[] names = { "Svetlana Omelchenko", "Claire O'Donnell", "Sven Mortensen", "Cesar Garcia" };
IEnumerable <string> queryFirstNames =
from name in names
let firstName = name.Split(' ')[0]
select firstName;
// SubQueries
var queryGroupMax =
from student in d.students
group student by student.Year into studentGroup
select new
{
Level = studentGroup.Key,
HighestScore =
(from student2 in studentGroup
select student2.ExamScores.Average())
.Max()
};
// Query Syntax
// Query #1
IEnumerable <int> numbersList = numbers1.Concat(numbers2);
IEnumerable <int> filteringQuery =
from number in numbersList
where number < 3 || number > 7
select number;
// Query #2
IEnumerable <int> orderingQuery =
from num in numbersList
where num < 3 || num > 7
orderby num ascending
select num;
// Method Syntax
// Query #1
double average = numbers1.Average();
// Query #2
IEnumerable <int> concatedValues = numbers1.Concat(numbers2);
// Query #3
IEnumerable <int> largeNumbersQuery = numbers2.Where(c => c > 15);
// Mixed query and method syntax
// Query #1
int numCount1 =
(from num in numbers1
where num < 3 || num > 7
select num).Count();
// Query #2
IEnumerable <int> numbersQuery =
from num in numbers1
where num < 3 || num > 7
select num;
int numCount2 = numbersQuery.Count();
IEnumerable <int> queryFactorsOfFour =
from num in numbers1.Concat(numbers2)
where num % 4 == 0
select num;
List <int> factorsofFourList = queryFactorsOfFour.ToList();
// OUTPUT!!
Console.Write("Press any key to continue. . .");
Console.ReadKey();
}
