Example of dictionary

Dictionary Dictionaries
Must contain a namespace System.Collection.Generic 
    Dictionary Every element in it is a key value pair ( It's made up of two elements ： Key and value ) 
    The key must be unique , And values don't need to be unique  
    Keys and values can be of any type ( such as ：string, int, Custom type , wait ) 
    The time to read a value through a key is close to O(1) 
    The partial order between key value pairs can not be defined
// Definition
Dictionary<string, string> openWith = new Dictionary<string, string>();
 
// Additive elements
openWith.Add(“txt”, “notepad.exe”);
openWith.Add(“bmp”, “paint.exe”);
openWith.Add(“dib”, “paint.exe”);
openWith.Add(“rtf”, “wordpad.exe”);
 
// Value
Console.WriteLine(“For key = “rtf”, value = {0}.”, openWith[“rtf”]);
 
// Change value
openWith[“rtf”] = “winword.exe”;
Console.WriteLine(“For key = “rtf”, value = {0}.”, openWith[“rtf”]);
 
// Traverse key
foreach (string key in openWith.Keys)
{
Console.WriteLine(“Key = {0}”, key);
}

// Traverse value
foreach (string value in openWith.Values)
{
    Console.WriteLine("value = {0}", value);
}

// Traverse value, Second Method
Dictionary<string, string>.ValueCollection valueColl = openWith.Values;
foreach (string s in valueColl)
{
    Console.WriteLine("Second Method, Value = {0}", s);
}

// Ergodic dictionary
foreach (KeyValuePair<string, string> kvp in openWith)
{
Console.WriteLine(“Key = {0}, Value = {1}”, kvp.Key, kvp.Value);
}

// Add existing elements 
try
{
    openWith.Add("txt", "winword.exe");
}
catch (ArgumentException)
{
    Console.WriteLine("An element with Key = \"txt\" already exists.");
}

// Remove elements 
openWith.Remove("doc");
if (!openWith.ContainsKey("doc"))
{
    Console.WriteLine("Key \"doc\" is not found.");
}

// The judgment key exists
if (openWith.ContainsKey(“bmp”)) // True {
Console.WriteLine(“An element with Key = “bmp” exists.”);
}
The parameter is a custom type
First define the class
class DouCube
{
public int Code { get { return _Code; } set { _Code = value; } } private int _Code;
public string Page { get { return _Page; } set { _Page = value; } } private string _Page;
}
then

// Declare and add elements 
Dictionary<int, DouCube> MyType = new Dictionary<int, DouCube>();
for (int i = 1; i <= 9; i++)
{
    DouCube element = new DouCube();
    element.Code = i * 100;
    element.Page = "http://www.doucube.com/" + i.ToString() + ".html";
    MyType.Add(i, element);
}

// Traversing elements 
foreach (KeyValuePair<int, DouCube> kvp in MyType)
{
    Console.WriteLine("Index {0} Code:{1} Page:{2}", kvp.Key, kvp.Value.Code, kvp.Value.Page);
} 

Common properties
    name     explain
    Comparer     Gets the parameter used to determine whether the keys in the dictionary are equal IEqualityComparer.
    Count        Get included in Dictionary<TKey, TValue> The key / The right number .
    Item         Gets or sets the value associated with the specified key .
    Keys         Get contains Dictionary<TKey, TValue> The set of keys in .
    Values       Get contains Dictionary<TKey, TValue> The set of values in .
Common methods
    name     explain
    Add                 Adds the specified key and value to the dictionary .
    Clear               from Dictionary<TKey, TValue> Remove all keys and values from .
    ContainsKey         determine Dictionary<TKey, TValue> Whether to include the specified key .
    ContainsValue       determine Dictionary<TKey, TValue> Whether to include a specific value .
    Equals(Object)      Determine the specified Object Is it equal to the current Object. （ Inherited from Object.）
    Finalize            Allow objects in “ Garbage collection ” Attempt to free resources and perform other cleanup operations before recycling . （ Inherited from Object.）
    GetEnumerator       Return to loop access Dictionary<TKey, TValue> The enumerator of .
    GetHashCode         Used as a hash function of a specific type . （ Inherited from Object.）
    GetObjectData       Realization System.Runtime.Serialization.ISerializable Interface , And return serialization Dictionary<TKey, TValue> Data required by the instance .
    GetType             Get the current instance's Type. （ Inherited from Object.）
    MemberwiseClone     Create current Object Shallow copy of . （ Inherited from Object.）
    OnDeserialization    Realization System.Runtime.Serialization.ISerializable Interface , And raise the deserialization event after deserialization .
    Remove              from Dictionary<TKey, TValue> Remove the value of the specified key from the .
    ToString            Returns a string representing the current object . （ Inherited from Object.）
    TryGetValue         Gets the value associated with the specified key .

using System;
using System.Collections.Generic;// Collections and containers of generic namespaces system.collection.generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication39
{
class Program
{
enum enum1
{ Monday , Tuesday , Wednesday , Thursday , Friday };
static void Main(string[] args)
{
Dictionary<string,int> zidian=new Dictionary<string,int>();// Defines a dictionary , Inside pass key The type of value and the type of value to be passed in
zidian.Add(“ A no. ”,45);
zidian.Add(“ Number two ”,43);
int count=zidian[“ Number two ”];
Console.WriteLine(count);
bool boo = zidian.ContainsKey(“ A no. ”);// Whether to include this key
Console.WriteLine(boo);
boo = zidian.ContainsValue(40);// Whether to include this value
Console.WriteLine(boo);
//zidian.Clear();// Clear the dictionary
//zidian.Remove()// Remove the position of the specified key
int a = 0;
zidian.TryGetValue(“ A no. ”,out a);// Assign the value in key one to a
int c=zidian.Count();// View the contents of the key ;
Console.WriteLine;
Console.WriteLine(a);
Dictionary<enum1, string> zidian2 = new Dictionary<enum1, string>();
zidian2.Add(enum1. Monday , “ Go to work ”);
zidian2.Add(enum1. Tuesday , “hsdf”);

        Console.ReadKey();
    }
}

}