V2AS问路
C# 通关手册(持续更新......)
阅读原文时间：2022年05月22日阅读：2

String

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-1

ignoreCase: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";

    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 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;

    string str="我好喜欢你";

    bool b1=str.StartsWith("好");//b1=false;

    bool b2-str.EndsWith("你");//b2=true;

    string str1="asd";
    string str2="ert";

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

  • 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;

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

  • 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"

  • 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";

  • 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"};

  • 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";

  • 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"};

  • 出去两边的空格

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

  • 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";

属性

方法

List

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


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"]


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);
}


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());

属性

方法

HashTable

  • 线程安全，单线程性能不如Dictionary

    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");

    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");

    using System;
    using System.Collections;

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

    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Key
    foreach (object key in keys)
    {
    //通过Key来获取Value
    Console.WriteLine($"{key}={table[key]}");
    }

    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DictionaryEntry
    foreach (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}");
    }

    using System;
    using System.Collections;

    Hashtable table = new Hashtable();
    int Count = table.Count;

    using System;
    using System.Collections;

    Hashtable table = new Hashtable();
    table.Clear();

    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

using System.Collections.Generic;

Dictionary<int,string > dict = new Dictionary<int,string>();

dict.Add(1,"111");

dict.Add(2,"222");


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" );



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}


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}");
}


using System.Collections.Generic;

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


using System.Collections.Generic;

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


using System.Collections.Generic;

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


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。

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

    // A B C D

    hashSet.Contains("D")

    hashSet.Remove(item);

    hashSet.Clear()

    HashSet setA = new HashSet() { "A", "B", "C", "D" };
    HashSet setB = new HashSet() { "A", "B", "C", "X" };
    HashSet setC = new HashSet() { "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.");

  • 输出setA setB中的所有元素

    using System;
    using System.Collections.Generic;

    HashSet setA = new HashSet() { "A", "B", "C", "D", "E" };
    HashSet setB = new HashSet() { "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

  • 输出setA和setB集合中都有的元素

    using System;
    using System.Collections.Generic;

    HashSet setA = new HashSet() { "A", "B", "C", "D", "E" };
    HashSet setB = new HashSet() { "A", "B", "C", "X", "Y" };
    setA.IntersectWith(setB);
    // A B C

  • 输出setA集合中有但setB集合中没有的元素

    using System;
    using System.Collections.Generic;

    HashSet setA = new HashSet() { "A", "B", "C", "D", "E" };
    HashSet setB = new HashSet() { "A", "B", "C", "X", "Y" };
    setA.ExceptWith(setB);
    // D E

    HashSet setA = new HashSet() { "A", "B", "C", "D", "E" };
    HashSet setB = new HashSet() { "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

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);
}

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

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


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


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

Thread

//threadMain
Console.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...");

//threadB
private void test() {
   while (true) {
   Console.WriteLine($"test:{DateTime.Now.Ticks}");
   }
}

//threadA
private 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");
}


//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
}


//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

using System;

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

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