Index in C #

usingSystem;usingSystem.Collections;usingSystem.Collections.Generic;usingSystem.Linq;usingSystem.Text;usingSystem.Threading.Tasks;namespacenettest{/** * The indexer is syntactically convenient for you to create a class, struct, or interface that the client application can access as an array.     Indexers are often implemented in types that are primarily used to encapsulate internal collections or arrays.     * Indexers allow instances of a class or struct to be indexed in the same way as an array, and indexers are similar to attributes, unlike indexers where access is a parameter. * Indexer and array comparison: * (1) indexer index value (index) type Unrestricted * (2) indexer allows overloading * (3) indexer is not a variable * Indexer and attribute different points * (1) attribute is identified by name, indexer is labeled as function     Knowledge * (2) indexers can be overloaded, properties cannot * (3) Indexers cannot be declared static, properties can * indexer values do not belong to variables; Therefore, indexer values cannot be passed as ref or out parameters. * **/     Public classIndexclass {PrivateHashtable name =NewHashtable (); //1: Access values via key         Public string  This[intIndex] {            Get{returnName[index]. ToString (); }            Set{name. ADD (index, value); }        }        //2: Access key via Values         Public int  This[stringAName] {            Get            {                //Hashtable is actually stored in the DictionaryEntry (dictionary) type, if you want to traverse a hashtable, you need to use the DictionaryEntry                foreach(DictionaryEntry Dinchname) {                    if(d.value.tostring () = =aName) {                        returnConvert.ToInt32 (D.key); }                }                return-1; }            Set{name.            ADD (value, aName); }        }    }    //Interface, index     Public InterfaceISomeInterface {//Indexer declaration:        int  This[intIndex] {            Get; Set; }    }    //implementing the interface.     Public classIndexerclass:isomeinterface {Private int[] arr =New int[ -];  Public int  This[intIndex//Indexer Declaration        {            Get            {                //The Arr object would throw IndexOutOfRange exception.                returnArr[index]; }            Set{Arr[index]=value; }        }    }}

 Static voidMain (string[] args) {            //use of the first type of indexerIndexclass Indexer =NewIndexclass (); indexer[1] ="Zhang San";//use of the set accessorindexer[2] ="John Doe"; Console.WriteLine ("the name is numbered 1:"+ indexer[1]);//use of Get accessorsConsole.WriteLine ("the name is numbered 2:"+ indexer[2]);            Console.WriteLine (); //use of the second type of indexerConsole.WriteLine ("the number of the Zhang San is:"+ indexer["Zhang San"]);//use of Get accessorsConsole.WriteLine ("the number of the John Doe is:"+ indexer["John Doe"]); indexer["Harry"] =3;//use of the set accessorConsole.WriteLine ("the number of the Harry is:"+ indexer["Harry"]);            Console.WriteLine (); Indexerclass Test=NewIndexerclass (); System.Random Rand=NewSystem.Random (); //Call the indexer-initialize its elements.             for(inti =0; I <Ten; i++) {Test[i]=Rand.            Next (); }             for(inti =0; I <Ten; i++) {System.Console.WriteLine ("Element #{0} = {1}", I, test[i]);        } console.readline (); }

Index in C #