C#6新特性

1.自動屬性增強

public bool ITuest { get; set; } = true;

 public string FirstName { get; } = "aehyok";

2.拉姆表達式作爲函數體

 public int Move(int x, int y) => x + y;

3.引用靜態類using static

 public double ReturnNum() =>  Acos(3);

4.空值判斷null

int? length = customers?.Count;
 int first = (int)customers?[0];

5.字符串嵌入值

  public string MakeStr()
        {
            string firstName = "ligen";
            string lastName = "wanli";
            return string.Format("one is /{firstName},two is /{lastName}");
        }

6.nameof表達式nameof expressions

public static void AddCustomer(Customer customer)

{

    if (customer == null)

    {

        throw new ArgumentNullException(nameof(customer));

    }

}
7.帶索引的對象初始化器Index initializers
var numer = new Dictionary<int, string> {[4] = "s33" };
8


try

{

    res = await Resource.OpenAsync(…); // You could do this. …

}

catch (ResourceException e)

{

    await Resource.LogAsync(res, e); // Now you can do this …

} finally

{

    if (res != null)

        await res.CloseAsync(); // … and this.

}

9、catch和finally 中的 await —— Await in catch and finally blocks

 在C#5.0中，await關鍵字是不能出現在catch和finnaly塊中的。而在6.0中

            try
            {
                res = await Resource.OpenAsync(…); // You could do this. … 
            }
            catch (ResourceException e)
            {
                await Resource.LogAsync(res, e); // Now you can do this … 
            } finally
            {
                if (res != null)
                    await res.CloseAsync(); // … and this. 
            } 

10Parameterless struct ctors 無參數的結構體構造函數

public FractionStruct( int a, int b) { A = a; B = b; }

public FractionStruct() : this(0, 1) { }

結構體可以提供自定義的無參數構造函數了。

new FractionStruct()

default(FractionStruct)

new是調用無參數構造函數。

default是不調用無參數構造函數。

11.Null propagation 空傳播

v?.A

v?["B"]

v?.ToString()

對象爲null時不調用屬性，索引器，方法等，表達式返回null，和Swift中的用法相似