Ylbtech-languagesamples-indexers_2 (Indexer)

Ylbtech-microsoft-csharpsamples:ylbtech-languagesamples-indexers_2 (Indexer)

1.A, example (sample) back to top

indexers_2 Example

This example shows how a C # class declares an indexer to represent a collection of similar arrays of different kinds of things. For additional information, see Properties (C # Programming Guide).

Safety Instructions
This code example is provided to illustrate a concept that does not represent the most secure coding practice, so you should not use this code example in an application or Web site. Microsoft assumes no responsibility for incidental or consequential damages arising from the use of this code sample for other purposes.

To build and run the Indexers_2 sample in Visual Studio

• On the Debug menu, click Start Without Debugging.

To build and run the Indexers_2 sample from the command line

• At the command prompt, type the following command:

  CSC indexers_2.csindexers_2

1.B, sample code back to top

1.b.1, Indexers_2.cs

//Copyright (C) Microsoft Corporation. All rights reserved. //This code is published in compliance with//Microsoft Public License (MS-PL,http://opensource.org/licenses/ms-pl.html) of the terms. ////Copyright (C) Microsoft Corporation. All rights reserved. //Indexedproperty.csusingSystem; Public classdocument{//The following types allow you to view documents in a similar way to a group of words:     Public classwordcollection {ReadOnlyDocument document;//include document        Internalwordcollection (document D) {document=D; }        //Helper Function--Search in the character array "text" starting from the character "begin"//the word "wordCount". If less than//WordCount The number of words, false is returned. The "Start" and//"Length" is set to the position and length of the word in the text:        Private BOOLGetword (Char[] text,intBeginintWordCount, out intStart out intlength) {             intEnd =text.            Length; intCount =0; intInword =-1; Start= length =0;  for(inti = begin; I <= end; ++i) {BOOLIsletter = i < end &&char.isletterordigit (Text[i]); if(Inword >=0)                 {                    if(!isletter) {                        if(count++ = =WordCount) {Start=Inword; Length= i-Inword; return true; } Inword= -1; }                }                Else                 {                    if(isletter) Inword=i; }            }            return false; }        //gets and sets the indexer that contains the words in the document:         Public string  This[intIndex] {            Get             {                 intstart, length; if(Getword (document). Textarray,0, Index, outStart, outlength)) return New string(document.                Textarray, start, length); Else                    Throw NewIndexOutOfRangeException (); }            Set             {                intstart, length; if(Getword (document). Textarray,0, Index, outStart, outlength)) {                    //Replace the string "value" with the Start/length at//Word:                    if(Length = =value. Length) {array.copy (value. ToCharArray (),0, document.                    Textarray, start, length); }                    Else                     {                        Char[] NewText =New Char[Document. Textarray.length +value. Length-length]; Array.copy (document. Textarray,0, NewText,0, start); Array.copy (value. ToCharArray (),0, NewText, start, value.                        Length); Array.copy (document. Textarray, start+length, NewText, start+value. Length, document. Textarray.length-Start-length); Document. Textarray=NewText; }                }                                    Else                    Throw NewIndexOutOfRangeException (); }        }        //gets the count of words in the containing document:         Public intCount {Get             {                 intCount =0, start =0, length =0;  while(Getword (document). Textarray, start + length,0,                                                outStart outlength)) ++count; returncount; }        }    }    //the following types allow viewing of documents in a similar character array// :     Public classcharactercollection {ReadOnlyDocument document;//include document        Internalcharactercollection (document D) {document=D; }        //gets and sets the indexer that contains the characters in the document:         Public Char  This[intIndex] {            Get             {                 returndocument.             Textarray[index]; }            Set{document. Textarray[index]=value; }        }        //gets the count of characters in the containing document:         Public intCount {Get             {                 returndocument.             Textarray.length; }        }    }    //because the type of the field has an indexer,//Therefore, these fields appear as indexed properties:     Publicwordcollection Words;  Publiccharactercollection characters; Private Char[] Textarray;//the text of the document.      PublicDocument (stringInitialtext) {Textarray=Initialtext.tochararray (); Words=NewWordcollection ( This); Characters=NewCharactercollection ( This); }     Public stringText {Get         {            return New string(Textarray); }    }}classtest{Static voidMain () {Document D=NewDocument ("Peter Piper picked a peck of pickled peppers. How many pickled peppers did Peter Piper pick?"        ); //Change the word "Peter" to "Penelope":         for(inti =0; i < D.words.count; ++i) {if(D.words[i] = ="Peter") D.words[i]="Penelope"; }        //change the character "P" to "P "         for(inti =0; i < D.characters.count; ++i) {if(D.characters[i] = ='P') D.characters[i]='P';    } Console.WriteLine (D.text); }}

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Ylbtech-languagesamples-indexers_2 (Indexer)