C#中多维数组[,]和交错数组[][]的区别

int [,] test1 = new int [3,3];

int [,] test1 = {
            {1,2,3},
            {1,2,3},
            {1,2,3},
        };

int [][] test1 = new int[5][];

int [][] test1 = new int[][];　　　　//注意，此的声明方式是错的

int [][] test1 = {
    new int[] {1,2,3,4},
    new int[] {1,2,3},
    new int[] {1,2}
}；

int [,] test1 = {
            {1,2,3,4},
            {1,2,3},
            {1,2}
        };         //这样是错的，长度必须一致

int [,] test1 = new int [4,5] {
            {1,2,3,4,5},
            {1,2,3},
            {1,2,3}
        }；　　　　　　　　//这样也是错误的，长度必须一致，必须为每一个位置赋值

int [,] test1 = {
            {1,2,3},
            {1,2,3},
            {1,2,3}
        };

int [][] test1 = {
          new int[] {1,2,3,4},　　　　 //new int[4] {1,2,3,4}
          new int[] {1,2,3},  　　　　//new int[3] {1,2,3}
          new int[] {1,2}
      }；

       int [,] test1 = {
           {1,2,3},
           {1,2,3},
           {1,2,3}
       };
       Console.WriteLine(test1.Length);
输出为   9

int [][] test1 = {
     new int[] {1,2,3},
     new int[] {1,2,3},
     new int[] {1,2,3},
 };
 Console.WriteLine(test1.Length);
 输出为 3

using System.Collections.Generic;        //头部引入

    //main中的代码
        static void Main(string[] args)
        {
            List<string> list = new List<string>();

            Console.ReadKey();
        }

        static void Main(string[] args)
        {
            List<string> list = new List<string>();
            //增加
            list.Add("a");
            list.Add("b");
            list.Add("c");
            list.Add("d");
            list.Add("e");
            list.Add("f");
            list.Add("g");
            Console.ReadKey();
        }

List<string> list = new List<string>(){"a","b","c","d","e","f"}; 

List<string> list = new List<string>{"a","b","c","d","e","f"};

//以上两种方法都可以，注意后面有没有 ()

    public class Test
    {
        public int x;
        public int y;
        public void What()
        {
            Console.WriteLine(x + y);
        }
    }

       static void Main(string[] args)
        {
            List<Test> list = new List<Test>()
            {
                new Test{x=1,y=6},
                new Test{x=8,y=6},
                new Test{x=4,y=8},
                new Test{x=5,y=7},
                new Test{x=3,y=3},
                new Test{x=6,y=6},
                new Test{x=9,y=666},
                new Test{x=7,y=6},
            };
            Console.ReadKey();
        }

    public class Test
    {
        public int x;
        public int y;
        public void What()
        {
            Console.WriteLine(x + y);
        }
    }
    class Program
    {
        static void Main(string[] args)
        {
            List<Test> list = new List<Test>()
            {
                new Test{x=1,y=6},
                new Test{x=8,y=6},
                new Test{x=4,y=8},
                new Test{x=5,y=7},
                new Test{x=3,y=3},
                new Test{x=6,y=6},
                new Test{x=9,y=666},
                new Test{x=7,y=6},
            };
            Console.ReadKey();
        }
    }