C#6.0新特性
阿新 • • 發佈:2019-02-05
首先
自動屬性初始化增強
public class Customer { public string First { get; set; } = "Jane"; public string Last { get; set; } = "Doe"; }
public class Customer { public string First { get; } = "Jane"; public string Last { get; } = "Doe"; }
public class Customer { //只讀的屬性 public stringName { get; }; //在初始化方法中賦值,可行~ public Customer(string first, string last) { Name = first + " " + last; } }
在C#5.0中是不可行的 如下圖:
方法函式支援lambda寫法 如下:
public void Print() => Console.WriteLine(First + " " + Last);
支援直接匯入名稱空間一樣匯入靜態類,而不用在程式碼中使用靜態類名 如下:
//靜態匯入Console using staticSystem.Console; using static System.Math; using static System.DayOfWeek; class Program { static void Main() { //直接使用方法而不用Console.WriteLine WriteLine(Sqrt(3*3 + 4*4)); WriteLine(Friday - Monday); } }
擴充套件方法,(這個不是很懂,解釋不好請原諒)
在Main類中靜態的匯入你要擴充套件的型別,然後寫你需要擴充套件的方法..?.. - -,不懂..
using static System.Linq.Enumerable; // The type, not the namespace class Program { static void Main() { var range = Range(5, 17); // Ok: not extension var odd = Where(range, i => i % 2 == 1); // Error, not in scope var even = range.Where(i => i % 2 == 0); // Ok } }
非空的語法糖如下:
int? first = customers?[0].Orders.Count(); //上面的寫法等同於下面 int? first = (customers != null) ? customers[0].Orders.Count() : null;
字串格式化新玩法:
//原來的,我們需要這樣.. var s = String.Format("{0} is {1} year{{s}} old", p.Name, p.Age); //C#6.0中,直接如下: var s = $"{p.Name} is {p.Age} year{{s}} old"; //在{}中甚至可以是任意的..(單詞不會..表示式還是什麼鬼.. - -,)反正如下: var s = $"{p.Name,20} is {p.Age:D3} year{{s}} old"; var s = $"{p.Name} is {p.Age} year{(p.Age == 1 ? "" : "s")} old";
索引初始化:
var numbers = new Dictionary<int, string> { [7] = "seven", [9] = "nine", [13] = "thirteen" };
異常過濾器:
如果When中用括號括起來的表示式計算結果為true,catch塊中執行,否則異常持續。
( - -,然而我也並沒有搞懂..求大神解釋..)
try { … } catch (MyException e) when (myfilter(e)) { … }
可非同步等待的Catch塊:
Resource res = null; 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. }
基本到此就結束了, - -,水平有限.不好與不完善的地方請指出..免得誤導大家..