C# 6.0可能的新特性

1、主构造函数（Primary Constructors）

主构造函数给类中的变量赋值

Before

public class Point { private int x, y; public Point(int x, int y) this.x = x; this.y = y; } }

 After

public class Point(int x, int y) { private int x, y; }

2、自动属性赋值（Auto Properties）

Before

class Point { public int X { get; private set; } public int Y { get; private set; } public Point() { this.X = 100; this.Y = 100; } }

After

class Point { public int X { get; private set; } = 100; public int Y { get; private set; } = 100; }

3、using静态类（Static type using statements;）

using会把引用类的所有静态方法导入到当前命名空间

Before

public double A { get { return Math.Sqrt(Math.Round(5.142)); } }

After

using System.Math; ... public double A { get { return Sqrt(Round(5.142)); } }

4、Property Expressions Before

public double Distance { get { return Math.Sqrt((X * X) + (Y * Y)); } }

After

public double Distance => Math.Sqrt((X * X) + (Y * Y));

初看起来像Lambda表达式，其实和Lambda无关系。

5. Method Expressions Before

public Point Move(int dx, int dy) { return new Point(X + dx1, Y + dy1); }

After

public Point Move(int dx, int dy) => new Point(X + dx, Y + dy);

这个和Property Expressions类似

6、Params for enumerables Before

Do(someEnum.ToArray()); ... public void Do(params int[] values) { ... }

After

Do(someEnum); public void Do(params IEnumerable<Point> points) { ... }

以前params是只可以修饰array类型的参数，现在多了一些类型

7、Monadic null checking(null检查运算符) Before

if (points != null) { var next = points.FirstOrDefault(); if (next != null && next.X != null) return next.X; } return -1;

After

var bestValue = points?.FirstOrDefault()?.X ?? -1;

这个少了好几行代码，赞啊 

8、Constructor type parameter inference Before

var x = MyClass.Create(1, "X"); ... public MyClass<T1, T2> Create<T1, T2>(T1 a, T2 b) { return new MyClass<T1, T2>(a, b); }

After

var x = new MyClass(1, "X");

9、 Inline declarations for out params(内联out参数定义) Before

int x; int.TryParse("123", out x);

After

int.TryParse("123", out int x);

说实话，，这个很常用。

当然，C# 6.0的全部新特性不止这么多，限于篇幅，就整理这些，若想了解更多，请参考下面的链接。

参考资料：

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