Object-oriented basis-indexer

String in C # is the ability to access the characters in an object through an indexer, but cannot modify the value of a character.

Let's look at the definition of indexers in string, such as.

The indexer, like a property, has a Get method, but does not have a set method, so this is why a variable of type string in C # is read-only.

　　

Now let's write our own indexer:

1     class Program2     {3         Static voidMain (string[] args)4         {5Test test =NewTest ();6Console.WriteLine ("Test[1] = {0},test[2] = {1}", test[1],test[2]);7 8test[1] ="Cai Anchor";9test[2] ="Shi Jin Ai";TenConsole.WriteLine ("Test[1] = {0},test[2] = {1}", test[1], test[2]); One  AConsole.WriteLine ("overloading of indexers:"+ test["Winchang",5]); -         } -     } the  -      Public classTest -     { -         Private stringName1 ="Chen Xinhong"; +         Private stringName2 ="Liu Guanhuo"; -  +          Public string  This[intIndex] A         { at             Get -             { -                 if(Index = =1) -                 { -                     returnname1; -                 } in                 Else if(Index = =2) -                 { to                     returnname2; +                 } -                 Else the                 { *                     Throw NewException ("the value of the index is out of range"); $                 }Panax Notoginseng             } -             Set  the             { +                 if(Index = =1) A                 { theName1 =value; +                 } -                 Else if(Index = =2) $                 { $Name2 =value; -                 } -                 Else the                 { -                     Throw NewException ("the value of the index is out of range");Wuyi                 } the             } -         } Wu         //indexers can also be overloaded. -          Public string  This[stringStrintx] About         { $             Get  -             { -                 returnSTR +x; -             } A         } +}

Output Result:

As we see, indexers have get and set methods like properties, and can be overloaded like functions in a class.

In the ADO technology, indexers are frequently used frequently.

Object-oriented basis-indexer