C#通关手册(持续更新......)

转载请注明来源 https://www.cnblogs.com/brucejiao/p/16188865.html 谢谢！
转载请注明来源 https://www.cnblogs.com/brucejiao/p/16188865.html 谢谢！
转载请注明来源 https://www.cnblogs.com/brucejiao/p/16188865.html 谢谢！

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String

常用静态方法

string.Compare(string str1,string str2,bool ignoreCase)

按照字典顺序比较字符串当str1 > str2时，返回1当str1 = str2时，返回0当str1 < str2时，返回-1ignoreCase:true 忽略大小写

string.Concat(string str1,string str2)

　string str=string.Concat("c","#"); //str="c#";

String.Format(string str)

string str=String.Format("今年是{0}年","2022");//str="今年是2022年";

string.IsNullOrEmpty(string str1)

• 判断字符是否为null或者为空，返回值为bool

string str2="";bool b2=string.IsNullOrEmpty(str2);//b2=true;string str3=null;bool b3=string.IsNullOrEmpty(str3);//b3=true;

string.Join(string str,string[] strArr)

• 将数组strArr中的内容拼接成一个新的字符串，并在对应数组的每两项间添加分隔符str

string strs=string.Join(",",string[]{"w","e","r","t"});//strs="w,e,r,t";

split去重

string update_invoice = FINVO System.CollectionICENUMBER + "," + invoiceNumber; // 追加发票号string[] oldInvoiceList = update_invoice.Split(new Char[] { ',' });string update_invoice_str = string.Join(",", oldInvoiceList.Distinct().ToArray());

Contains

• Contains 判断字符串中是否包含某个字符,返回bool值

string str="我爱编程";bool b=str.Contains("程");//b=true;

StartsWith/EndsWith

string str="我好喜欢你";bool b1=str.StartsWith("好");//b1=false;bool b2-str.EndsWith("你");//b2=true;

Equals

string str1="asd";string str2="ert";bool  b = str1.Equals(str2);  //b=false;bool <strName>.Equals(string str, StringComparison.OrdinalIgnoreCase)   //表示不区分大小写

IndexOf/LastIndexOf

• 判断字符串第一次出现（IndexOf）和最后一次出现（LastIndexOf ）的位置，如果没有出现过则返回值为-1

string str ="今天的雨很大，天很冷";int i=str.IndexOf("很"); //i=4;int i=str.LastIndexOf("很");//j=8;int m=str.IndexOf("小");//m=-1;

Replace

string str="好困呀";string s=str.Replace("困","精神");//s="好精神呀";

Insert

• 在字符串的index位置上插入字符，原来的字符依次后移，变成一个新的字符串

string str="夜深了";string s=str.Insert(1,"已经");// s="夜已经深了"

Remove

• 在字符串中移除从startIndex开始，长度为length的字符串，剩下的字符合为一个新的字符串( = .Remove(startIndex,length)??

string str="夜已经深了";string s=str.Remove(1,2);//s="夜深了";

Split

• 将字符串以sep数组中的字符分割，分割后得到的内容存到一个数组中（string[] .Split(params char[] sep);）

string str="我，真的、好困；呀";string[] s=str.Split(new char(){'，','、','；'});//s=string[]{"我","真的","好困","呀"};

Substring

• 取字符以index开始截取，并截取lenth个字符(string .Substring(index,lenth))

string str="还在下雨";string s=str.Substring(2,2);//s="下雨";

ToCharArray

• 将字符串转化为字符数组（.ToCharArray()）

string str="雨已经小了";char[] s=str.ToCharArray();//s=char[]{'雨',"已","经","小","了"};

Trim

• 出去两边的空格

string str=" aa ";string s=str.Trim();//s="aa";

ToUpper/ToLower

• ToUpper（转换为大写）和ToLower（转换为小写）

string s="RaSer";string s1=s.ToUpper();//s1="RASER";string s2=s.ToLower();//s2="raser";

API

属性

方法

List

创建List

using System.Collections.Generic;List<string> list = new List<string>();list.Add("a");

数组去重

using System;using System.Collections.Generic;using System.Linq;List<string> list1 = new List<string>() {"123","456","789","789" };// ["123","456","789","789"]List<string> newList =  list1.Distinct().ToList(); //["123","456","789"]   

数组是否包含

using System;using System.Collections.Generic;using System.Linq;List<string> list1 = new List<string>() {"123","456","789","789" };// ["123","456","789","789"]if(list1.Contains("123")){	 Console.WriteLine(true);}else{	 Console.WriteLine(false);}

数组分组

using System;using System.Collections.Generic;using  System.Linq;List<int>  sqlList = new List<int>();for(int i=0;i<100;i++){	sqlList.Add(i);}Console.WriteLine(sqlList.ToString());List<List<int>> sql_batch = sqlList.Select((x, i) => new { Index = i, Value = x })			.GroupBy(x => x.Index / 5) //分成5组			.Select(x => x.Select(v => v.Value).ToList())			.ToList();Console.WriteLine(sql_batch.ToString());

API

属性

方法

HashTable

• 线程安全，单线程性能不如Dictionary

创建Map

using System;  using System.Collections;Hashtable table =  new  Hashtable();//添加的是键值对 table.Add("name",  "zhangsan"); table.Add("age",  10); table.Add("gender",  "male");

删除指定键的元素

using System;using System.Collections;Hashtable table =  new  Hashtable();table.Add("age",  10);//通过Key来删除一个键值对 table.Remove("age");

修改元素

using System;using System.Collections;Hashtable table =  new  Hashtable();table.Add("age",  10);//通过Key来修改元素table["age"]  =  30;

遍历Keys

using System;using System.Collections;Hashtable table =  new  Hashtable();//添加的是键值对 table.Add("name",  "zhangsan");table.Add("age",  10);table.Add("gender",  "male");ICollection keys = table.Keys;//遍历刚刚获取到的所有的Keyforeach (object key in keys){    //通过Key来获取Value    Console.WriteLine($"{key}={table[key]}");}

遍历Keys-Values

using System;  using System.Collections;Hashtable table =  new  Hashtable();//添加的是键值对 table.Add("name",  "zhangsan"); table.Add("age",  10); //Hashtable中存储的元素类型是DictionaryEntryforeach (DictionaryEntry entry in table){   //获取一个键值对中的键   object key = entry.Key;   //获取一个键值对中的值   object value = entry.Value;   Console.WriteLine($"{key}={value}");}

获取HashTable中的键值对的数目

using System;using System.Collections;Hashtable table =  new  Hashtable();int Count = table.Count;

清空集合

using System;  using System.Collections;Hashtable table =  new  Hashtable();table.Clear();

判断Hashtable中是否包含了指定的键

using System;  using System.Collections;Hashtable table =  new  Hashtable();//添加的是键值对 table.Add("name",  "zhangsan"); table.Add("age",  10); bool result = table.Contains("age");

Dictionary

创建Map

using System.Collections.Generic;Dictionary<int,string > dict = new Dictionary<int,string>();dict.Add(1,"111");dict.Add(2,"222");

删除指定键的元素

using System.Collections.Generic;Dictionary< string , int > d = new Dictionary< string , int >();d.Add( "C#" , 2);d.Add( "VB" , 1);d.Add( "C" , 0);d.Add( "C++" , -1);//删除键为“C”的元素d.Remove( "C" );//删除键为“VB”的元素d.Remove( "VB" );

序列化为JSON对象

using Newtonsoft.Json;using System.Collections.Generic;Dictionary<string, int> dic = new Dictionary<string, int>() {    {"张三",1},    {"李四",2},};string result = JsonConvert.SerializeObject(dic);Console.WriteLine(result); //{"张三":1,"李四":2}

JSON对象反序列化Dictionary

using Newtonsoft.Json;using System.Collections.Generic;result = "{\"张三\":1,\"李四\":2}";Dictionary<string, int> dic2 = JsonConvert.DeserializeObject<Dictionary<string, int>>(result);foreach (var item in dic2){    Console.WriteLine($"{item.Key}---->{item.Value}");}

判断是否存在相应的key并显示

using System.Collections.Generic;Dictionary<int,string > dict = new Dictionary<int,string>();if (dict.ContainsKey(<key>)) {	 Console.WriteLine(dict[<key>]); }

遍历Keys

using System.Collections.Generic;Dictionary<int,string > dict = new Dictionary<int,string>();foreach (var item in dict.Keys){ Console.WriteLine( "Key:{0}" , item);}

遍历Values

using System.Collections.Generic;Dictionary<int,string > dict = new Dictionary<int,string>();foreach (var item in dict.Values){ Console.WriteLine( "value:{0}" , item);}

遍历整个字典

using System.Collections.Generic;Dictionary<int,string > dict = new Dictionary<int,string>();foreach (var item in dict){ Console.WriteLine( "key:{0} value:{1}" , item.Key, item.Value);}

HashSet

• 高性能且无序的集合，只能使用foreach来进行迭代，而无法使用for循环。

创建HashSet

using System; using System.Collections.Generic;HashSet<string> hashSet = new HashSet<string>();hashSet.Add("A");hashSet.Add("B");hashSet.Add("C");hashSet.Add("D");// A B C D

判断是否包含

hashSet.Contains("D")

移除某元素

hashSet.Remove(item);

删除所有元素

hashSet.Clear()

判断 HashSet 是否为某一个集合的完全子集

HashSet<string> setA = new HashSet<string>() { "A", "B", "C", "D" };HashSet<string> setB = new HashSet<string>() { "A", "B", "C", "X" };HashSet<string> setC = new HashSet<string>() { "A", "B", "C", "D", "E" };if (setA.IsProperSubsetOf(setC)) //是子集输出1，不是输出0   Console.WriteLine("setC contains all elements of setA.");if (!setA.IsProperSubsetOf(setB))   Console.WriteLine("setB does not contains all elements of setA.");

集合合并

• 输出setA setB中的所有元素

using System; using System.Collections.Generic;HashSet<string> setA = new HashSet<string>() { "A", "B", "C", "D", "E" };HashSet<string> setB = new HashSet<string>() { "A", "B", "C", "X", "Y" };setA.UnionWith(setB);foreach(string str in setA){   Console.WriteLine(str);}//最终setA的输出结果是 A B C D E X Y

交集

• 输出setA和setB集合中都有的元素

using System; using System.Collections.Generic;HashSet<string> setA = new HashSet<string>() { "A", "B", "C", "D", "E" };HashSet<string> setB = new HashSet<string>() { "A", "B", "C", "X", "Y" };setA.IntersectWith(setB);// A B C

差集

• 输出setA集合中有但setB集合中没有的元素

using System;using System.Collections.Generic;HashSet<string> setA = new HashSet<string>() { "A", "B", "C", "D", "E" };HashSet<string> setB = new HashSet<string>() { "A", "B", "C", "X", "Y" };setA.ExceptWith(setB);// D E

两个集合都不全有的元素

HashSet<string> setA = new HashSet<string>() { "A", "B", "C", "D", "E" };HashSet<string> setB = new HashSet<string>() { "A", "X", "C", "Y" };setA.SymmetricExceptWith(setB);foreach (string str in setA){  Console.WriteLine(str);}//对于这个示例，最终输出结果是BDEXY

SortedSet

创建SortedSet

using System;using System.Collections.Generic;SortedSet<string> set1 = new SortedSet<string>();set1.Add("CD");set1.Add("CD");set1.Add("CD");set1.Add("CD");Console.WriteLine("Elements in SortedSet1...");foreach (string res in set1) {		Console.WriteLine(res);}

API

Json

创建JSON

金蝶JSON

using Kingdee.BOS.JSON;JSONObject jsonObject = new JSONObject();jsonObject.Put("userName", dynamicObjectCollection[0]["USERNAME"]);jsonObject.Put("reason", backMsg);jsonObject.Put("bbcOrderNum",billNo);

C# JSON

using Newtonsoft.Json;using Newtonsoft.Json.Linq;JObject jObject = new JObject();jObject["recMobile"] = Convert.ToString(dynamicObject["FReceiverPhone"]);jObject["recTel"] = Convert.ToString(dynamicObject["FReceiverTel"]);

合并其他对象到属性

JObject obj = new JObject();obj.Add("name", "张三");obj.Add("birthday", DateTime.Now); //合并其他对象到当前对象的属性obj.Add("content", JToken.FromObject(new{    code = "zhangsan"}));//返回{	"name":"张三",	"birthday","2022-05-04",	"content":{		"code":"zhangsan"	}}

合并其他对象的属性，到当前对象

//合并其他JObject obj = new JObject();obj.Add("name", "张三");obj.Add("birthday", DateTime.Now);JObject obj2 = JObject.FromObject(new{    code = "lisi"});obj.Merge(obj2);//返回{	"name":"张三",	"birthday","2022-05-04",	"code ":"lisi"}

JSON解析

using Newtonsoft.Json;using Newtonsoft.Json.Linq;string jsonText = @"{ "input": {	'size': 193156, 	'type': 'image/png'}";JObject jobject = (JObject)JsonConvert.DeserializeObject(jsonText);decimal input_size = Convert.ToDecimal(jobject["input"]["size"]);//193156, 输入图片大小string input_type = jobject["input"]["type"].ToString();// "image/png"，输入图片类型

DateTime

字符串转时间

DateTime time= Convert.ToDateTime("2022-04-28 00:00:00");Console.WriteLine(time);

时间转字符串

DateTime dt_now = DateTime.Now;string time=dt_now.ToString("yyyy-MM-dd hh:mm:ss");Console.WriteLine(time);

时间字符串格式化 yyyy-MM-dd hh:mm:ss 转 yyMMdd

string time = Convert.ToDateTime("2019-08-28 00:00:00").ToString("yyMMdd");Console.WriteLine(time);

Thread

创建多线程 无参

//threadMainConsole.WriteLine("Main方法开始执行...");Thread threadA = new Thread(Execute);threadA.Start();Thread threadB = new Thread(test);threadB.Start();Console.WriteLine("Main方法执行结束...");//threadBprivate void test() {   while (true) {   Console.WriteLine($"test:{DateTime.Now.Ticks}");   }}//threadAprivate void Execute() {   Console.WriteLine("开始下载,此协程的Id是:" +            Thread.CurrentThread.ManagedThreadId);  int bill_count = billNoList.Count;  Thread.Sleep(5000 * bill_count);  foreach (string billNo in billNoList)  {    getIvnumber(billNo);  }  Console.WriteLine("下载完成");}

创建多线程 带参

//定义一个类，用于存放线程需要的数据和线程启动的方法public class MyThread{  private string data;//线程数据  public MyThread(string data)  {    this.data = data;  }  //线程启动方法  public void ThreadMain()  {    Console.WriteLine("Running in a thread, data: {0}", data);  }}static void Main(){  MyThread obj = new MyThread("info");//创建实例信息  Thread t3 = new Thread(obj.ThreadMain);//启动实例方法  t3.Start();}

//定义一个数据类型，传递给线程public struct Data{  public string Message;}//创建一个方法，将方法给线程的ParameterizedThreadStart委托static void ThreadMainWithParameters(object obj){  Data d = (Data)obj;  Console.WriteLine("Running in a thread, received {0}", d.Message);}static void Main(){  Data d = new Data { Message = "Info" };//创建一个数据实例  Thread t2 = new Thread(ThreadMainWithParameters);//创建线程  t2.Start(d);//启动线程，并传递参数}

线程启动 前台线程/后台线程

//前台线程//创建线程方法，以在主线程中调用static void ThreadMain(){  Console.WriteLine("Thread {0} started", Thread.CurrentThread.Name);  Thread.Sleep(3000);  Console.WriteLine("Thread {0} completed", Thread.CurrentThread.Name);}static void Main(){  Thread t1 = new Thread(ThreadMain);  t1.Name = "MyNewThread";  t1.Start();　　 Thread.Sleep(100);  Console.WriteLine("Main thread ending now...");  /*******************输出********************     *          Thread MyNewThread started   *     Main thread ending now...   *     Thread MyNewThread completed   * *****************************************/}

//后台线程static void Main(){  Thread t1 = new Thread(ThreadMain);  t1.Name = "MyNewThread";  t1.IsBackground = true;  t1.Start();  Thread.Sleep(100);  Console.WriteLine("Main thread ending now...");  /*******************输出********************   *     Thread MyNewThread started   *     Main thread ending now...   * *****************************************/}

前台线程:主线程默认启动方式为前台线程，主线程结束后，前台线程仍可以活动。后台线程：如果在线程启动前，将线程的IsBackground属性设置为true，主线程结束时，会终止新线程的执行（不论是否完成任务）。

Ramdom

生成随机数

using System;Random r = new Random();Console.WriteLine(r.Next(1,5));

转载请注明来源 https://www.cnblogs.com/brucejiao/p/16188865.html 谢谢！
转载请注明来源 https://www.cnblogs.com/brucejiao/p/16188865.html 谢谢！
转载请注明来源 https://www.cnblogs.com/brucejiao/p/16188865.html 谢谢！