关于自动属性和对象初始化器

当初始化类的对象时，如果有多个属性，考虑到每一种组合的话需要定义很多构造器，显然这是很麻烦的，通过对象初始化器可以很好地解决这个问题

1. 在类中对字段初始化；
2. 创建对象的时候使用对象初始化器；

 1 //在创建类的时候对其属性进行初始化
 2 class Polygon
 3     {
 4         public int NumSides { get; set; }
 5         public double SideLength { get; set; }
 6         public Polygon()
 7         {
 8             this.NumSides = 4;
 9             this.SideLength = 10.0;
10         }
11 }
12 //在创建对象时使用对象初始化器
13 static void DoWork()
14         {
15             // to do
16             Polygon square = new Polygon();
17             Polygon triangle = new Polygon { NumSides = 3 };
18             Polygon pentagon = new Polygon { SideLength = 15.5, NumSides = 5 };
19             Console.WriteLine("Square: number of sides is {0},length of each side is {1}",square.NumSides,square.SideLength);
20             Console.WriteLine("triangle: number of sides is {0},length of each side is {1}", triangle.NumSides, triangle.SideLength);
21             Console.WriteLine("pentagon: number of sides is {0},length of each side is {1}", pentagon.NumSides, pentagon.SideLength);
22         }
23
24         static void Main(string[] args)
25         {
26             try
27             {
28                 DoWork();
29             }
30             catch (Exception ex)
31             {
32                 Console.WriteLine(ex.Message);
33             }
34         }