C# 6.0 新特性-白红宇

C# 6.0 新特性

阅读量：6591 次

发布时间：2019-06-24

本文共 10986 字，大约阅读时间需要 36 分钟。

C# 6.0 加入了不少东西，C# 的语言风格变得更好了,周末忙了一上午做了一个demo. 直接代码上来

完整代码:

#define ASYNCusing System;using System.Collections.Generic;using System.Diagnostics;using System.IO;using System.Text;using System.Threading.Tasks;using static System.Math;namespace NewCharp6{    class Program    {        static void Main(string[] args)        {            //Initilizers for auto properties and function with lambda            var salesOrder = new SalesOrder();            Console.WriteLine("Begin to Test New In C# 6.0");            Console.WriteLine("=====================Auto Init Property  lambda In A class=======================");            Console.WriteLine("OrderNo:" + salesOrder.OrderNo);            Console.WriteLine("OrderCode:" + salesOrder.OrderCode);            Console.WriteLine("OrderInfo:" + salesOrder.OrderInfo);            Console.WriteLine("GetOrderInfo:" + salesOrder.GetOrderInfo());            Console.WriteLine("=====================Test Null Conditional Operators=======================");            Console.WriteLine("Here Will Output Null Value.............");            SalesInovice salesInvoice = new SalesInovice();            Console.WriteLine(salesInvoice.OrderList?[0].OrderNo);//sample Operator            Console.WriteLine(salesInvoice.salesReturn?.returnCode);//sample Operator            //Initializers the Orders And Retutn            Console.WriteLine("Here Will Output Actual Value After Initializer the Object.............");            salesOrder.OrderNo = Guid.NewGuid();            salesOrder.OrderCode = "OS0001";            salesInvoice.OrderList = new List
     
      ();            salesInvoice.OrderList.Add(salesOrder);            salesInvoice.salesReturn = new SalesReturn();            salesInvoice.salesReturn.returnNo = Guid.NewGuid();            salesInvoice.salesReturn.returnCode = "RT0001";            Console.WriteLine(salesInvoice.OrderList?[0].OrderNo + ":" + salesInvoice.OrderList?[0].OrderCode);            Console.WriteLine(salesInvoice.salesReturn?.returnNo + ":" + salesInvoice.salesReturn?.returnCode);            //Index Initializers            Console.WriteLine("Initializer An Collections With Index .............");            var returnDictionary = new Dictionary
      
       () { [0] = new SalesReturn() { returnNo = Guid.NewGuid(), returnCode = "RT001" }, [1] = new SalesReturn { returnNo = Guid.NewGuid(), returnCode = "RT002" } };            Console.WriteLine("Here Will Output the Dictionary：" + returnDictionary[0]?.returnNo + returnDictionary[0]?.returnCode);            var returnStrDictionary = new Dictionary
       
        () { ["One"] = new SalesReturn { returnNo = Guid.NewGuid(), returnCode = "RT001" }, ["Two"] = new SalesReturn { returnNo = Guid.NewGuid(), returnCode = "RT002" } };            Console.WriteLine("Here Will Output the Dictionary：" + returnStrDictionary["One"]?.returnNo + returnStrDictionary["One"]?.returnCode);            //Here Will Output All Object in the Dictionarys             foreach (KeyValuePair
        
          item in returnStrDictionary)            {                Console.WriteLine("Key:" + item.Key + string.Format("   {0}-{1}", item.Value.returnNo, item.Value.returnCode));            }            //Here will Output the math function Directly Before we Will use System.Math.abs But Now Just use abs             Console.WriteLine("=====================Using static NameSpace=======================");            Console.WriteLine("using static System.Math at the head firse");            Console.WriteLine("Output the abs value:" + Abs(-7));            //Exception Filter In C# 6.0#if ASPNET            Console.WriteLine("=====================Exception Filter In C# 6.0=======================");            try            {                try                {                    Console.WriteLine("begin to throw ASPNET EXCEPTION.........");                    throw new ExceptionHander("ASP.Net Exception");                }                catch (ExceptionHander ex) when (ExceptionHander.CheckEx(ex))                {//ASPNET EXCEPTION WILL NOT CATCH HERE                    Console.WriteLine("Exception Type:" + ex.Message + "Was Catch the Other was Missing .......");                }            }            catch (ExceptionHander ex)            {//ASPNET EXCEPTION WILL CATCH HERE                Console.WriteLine(ex.Message);            }#elif DATABASE            try            {                try                {                    Console.WriteLine("begin to throw DATABASE EXCEPTION.........");                    throw new ExceptionHander((int)ExType.DATABASE, "DataBase Exception");                }                catch (ExceptionHander ex) when (ExceptionHander.CheckEx(ex))                {                    Console.WriteLine("Exception Type:" + ex.Message + "Was Catch the Other was Missing .......");                }            }            catch (ExceptionHander ex)            {//DATABASE EXCEPTION WILL CATCH HERE                Console.WriteLine(ex.Message);            }#elif ASYNC            Console.WriteLine("========Begin To Test async in catch and finally blocks(C#6.0 Only)===============");            try            {                throw new Exception("Error Occur");            }            catch (Exception ex)            {                //TODO can't use the async In Mian                 // var returnAsync = await ProcessWrite(ex.Message);            }#endif            Console.ReadKey();        }        protected static SalesOrder GetSales()        {            SalesOrder salesOrder = new SalesOrder();            salesOrder.OrderCode = "SO001";            return salesOrder;        }        //async read and write        public async void ProcessWrite(string text)        {            string filePath = System.Environment.CurrentDirectory + "commonLog.txt";            await WriteTextAsync(filePath, text);        }        private async Task WriteTextAsync(string filePath, string text)        {            byte[] encodedText = Encoding.Unicode.GetBytes(text);            using (FileStream sourceStream = new FileStream(filePath,                FileMode.Append, FileAccess.Write, FileShare.None,                bufferSize: 4096, useAsync: true))            {                await sourceStream.WriteAsync(encodedText, 0, encodedText.Length);            };        }        public async void ProcessRead()        {            string filePath = @"temp2.txt";            if (File.Exists(filePath) == false)            {                Debug.WriteLine("file not found: " + filePath);            }            else            {                try                {                    string text = await ReadTextAsync(filePath);                    Debug.WriteLine(text);                }                catch (Exception ex)                {                    Debug.WriteLine(ex.Message);                }            }        }        private async Task
         
           ReadTextAsync(string filePath)        {            using (FileStream sourceStream = new FileStream(filePath,                FileMode.Open, FileAccess.Read, FileShare.Read,                bufferSize: 4096, useAsync: true))            {                StringBuilder sb = new StringBuilder();                byte[] buffer = new byte[0x1000];                int numRead;                while ((numRead = await sourceStream.ReadAsync(buffer, 0, buffer.Length)) != 0)                {                    string text = Encoding.Unicode.GetString(buffer, 0, numRead);                    sb.Append(text);                }                return sb.ToString();            }        }    }    public class SalesOrder    {        public Guid OrderNo { get; set; } = new Guid();        public String OrderCode { get; set; }        public Int32 Quanlity { get; set; }        public double UnitPrice { get; set; }        public String OrderInfo => string.Format("lambda to property demo {0}:{1}", OrderNo, OrderCode);//lambda for properyies         public String GetOrderInfo() => string.Format("lambda to function demo {0}:{1}", OrderNo, OrderCode);//lambda for functions     }    public class SalesInovice    {        public Guid InvoiceNo { get; set; }        public String InvoiceCode { get; set; }        public List
          
            OrderList { get; set; } public SalesReturn salesReturn { get; set; } } public class SalesReturn { public Guid returnNo { get; set; } public String returnCode { get; set; } } public class ExceptionHander : Exception { public int TypeofException { get; set; } = (int)ExType.ASPNET; public string Msg { get; set; } public ExceptionHander(int Type, string Message) : this(Message) { TypeofException = Type; } public ExceptionHander(String msg) { Msg = msg; } public static Boolean CheckEx(ExceptionHander ex) { if (ex.TypeofException.Equals(ExType.DATABASE)) { return true; } else { return false; } } } public enum ExType { DATABASE = 0, ASPNET = 1 }}

代码解读:

一.属性，方法的 lambda 表示法.

public class SalesOrder    {        public Guid OrderNo { get; set; } = new Guid();        public String OrderCode { get; set; }        public Int32 Quanlity { get; set; }        public double UnitPrice { get; set; }        public String OrderInfo => string.Format("lambda to property demo {0}:{1}", OrderNo, OrderCode);//lambda for properyies         public String GetOrderInfo() => string.Format("lambda to function demo {0}:{1}", OrderNo, OrderCode);//lambda for functions     }

二.空值判断更加简洁

Console.WriteLine(salesInvoice.OrderList?[0].OrderNo + ":" + salesInvoice.OrderList?[0].OrderCode);Console.WriteLine(salesInvoice.salesReturn?.returnNo + ":" + salesInvoice.salesReturn?.returnCode);

三. 集合根据index 初始化

Console.WriteLine("Initializer An Collections With Index .............");            var returnDictionary = new Dictionary
     
      () { [0] = new SalesReturn() { returnNo = Guid.NewGuid(), returnCode = "RT001" }, [1] = new SalesReturn { returnNo = Guid.NewGuid(), returnCode = "RT002" } };            Console.WriteLine("Here Will Output the Dictionary：" + returnDictionary[0]?.returnNo + returnDictionary[0]?.returnCode);

四. 支持异常过滤用在catch 后用when关键字

try            {                try                {                    Console.WriteLine("begin to throw DATABASE EXCEPTION.........");                    throw new ExceptionHander((int)ExType.DATABASE, "DataBase Exception");                }                catch (ExceptionHander ex) when (ExceptionHander.CheckEx(ex))                {                    Console.WriteLine("Exception Type:" + ex.Message + "Was Catch the Other was Missing .......");                }            }            catch (ExceptionHander ex)            {//DATABASE EXCEPTION WILL CATCH HERE                Console.WriteLine(ex.Message);            }

五.支持在catch 和 finally 上使用异步方法

GitHub Code 下载: https://github.com/ShenZhenMS/NewFeatureCSharp6.git

参考博客： http://www.cnblogs.com/henryzhu/p/new-feature-in-csharp-6.html

希望对大家有帮助.

转载于:https://www.cnblogs.com/QuickTechnology/p/5635155.html

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