初始化器的应用及语法

亦凉 2022-06-14 11:47 156阅读 0赞

using System;  
using System.Collections.Generic;  
using System.Linq;  
using System.Text;  
using System.Threading.Tasks;  
  
namespace Initialter  
\{  
    class Program  
    \{  
        static void Main(string\[\] args)  
        \{  
  
            //ObjectInitializer();  
            //InitializerAnonyousType();  
             //CollectionInitilaizer();  
  
        \}  
  
        //各种对象初始化  
        private static void ObjectInitializer()  
        \{  
            var student1 = new StudentName("Meimei", "wang");  
            //调用构造函数  
            var student2 = new StudentName \{ FirstName = "Meimei", LastName = "wang" \};  
            var student3 = new StudentName \{ ID = 100 \};  
            var student4 = new StudentName("Lei", "Li") \{ ID = 101 \};  
            Console.WriteLine(student1.ToString());  
            Console.WriteLine(student2.ToString());  
            Console.WriteLine(student3.ToString());  
            Console.WriteLine(student4.ToString());  
        \}  
  
        //匿名类和匿名类的使用  
        private static void InitializerAnonyousType()  
        \{  
            //匿名类,是只读的  
            var pet = new \{ Age = 10, Name = "Miaomiao" \};  
  
            var Students = new List<StudentName> \{ new StudentName("Li", "Li"), new StudentName("Mei", "Mei") \};  
            var StudentFrom = new List<StudentFrom>  
            \{  
                new StudentFrom\{FirstName="Li",City="Beijing"\},  
                 new StudentFrom\{FirstName="Wang",City="Shanghai"\},  
            \};  
  
            var joinquery = from s in Students  
                            join f in StudentFrom on s.FirstName equals f.FirstName  
                            select new \{ FirstName = s.FirstName, LastName = s.LastName, City = f.City \};  
            foreach (var temp in joinquery)  
            \{  
                Console.WriteLine("\{0\}\{1\}\{2\}", temp.FirstName, temp.LastName, temp.City);  
            \}  
        \}  
  
        //集合初始化器和dictionary初始化  
        private static void CollectionInitilaizer()  
        \{  
            var students = new List<StudentName>  
            \{  
                new StudentName\{FirstName="Mei",LastName="Mei",ID=100\},  
                new StudentName()\{FirstName="Lei",LastName="Lei",ID=101\},  
                new StudentName("Li","Li")\{ID=102\},  
                null  
            \};  
  
            foreach (var s in students)  
            \{  
                if (s != null)  
                \{  
                    Console.WriteLine(s.ToString());  
                \}                  
            \}  
  
            Dictionary<int, StudentName> studentsdic = new Dictionary<int, StudentName>  
            \{  
                \{111,new StudentName\{FirstName="Mei",LastName="Mei",ID=100\}\},  
                \{112,new StudentName()\{FirstName="Lei",LastName="Lei",ID=101\}\}  
            \};  
  
            foreach (var s in studentsdic)  
            \{  
                Console.WriteLine(s.Value.ToString());  
            \}  
        \}  
    \}  
  
    public class StudentName  
    \{  
        public string FirstName \{ get; set; \}  
        public string LastName \{ get; set; \}  
        public int ID \{ get; set; \}  
  
        public StudentName()  
        \{  
          
        \}  
        public StudentName(string first,string last)  
        \{  
            FirstName = first;  
            LastName = last;  
        \}  
        public override string ToString()  
        \{  
            return FirstName + " " + ID;  
        \}  
    \}  
  
    public class StudentFrom  
    \{  
        public string FirstName \{ get; set; \}  
  
        public string City \{ get; set; \}  
    \}  
\}