Bài giảng Lập trình C# 2010: Chương 5 - ĐH Công nghệ Đồng Nai

Bài giảng Lập trình C# 2010: Chương 5 - String Class có nội dung trình bày về: Constructor, String Field, String Operators, String Methods, DEMO String & Dictionary.

Abstraction Encapsulation

Inheritance

Polymorphism

private protected

public

from an existing class

• The existing class is called the

• The inherited class is called the

derived , subclass , or child

relationship with its base class

Inheritance

• Inheritance supports reusability

• Reusability – creation of object

functionality that may be used in multiple projects

• Methods with identical names have

different implementations

• The Select method is different for radio

buttons, check boxes, and list boxes

• Allows a single class to have more than

one method with different argument lists

How to create Class

get { return this m _strID ; }

set { this m _strID = value; }

}

public string N am e

{

get { return this m _strN am e; }

set { this m _strN am e = value; }

}

public string D escription

{

get { return this m _strD escription; }

set { this m _strD escription = value; }

}

public abstract void doSom ething();

Constructor

get { return this m _dPrice; }

set { this m _dPrice = value ; }

private string m _strISBN ;

private string m _strAuthor;

private string m _strTitle;

get { return this.m _strISBN ; }

set { this.m _strISBN = value; }

}

public string Author

{

get { return this.m _strAuthor; }

set { this.m _strAuthor = value; }

}

public string Title

{

get { return this.m _strTitle; }

set { this.m _strTitle = value; }

}

}

{

private string m _strArtist;

private string m _strTitle;

public CCom pactD isc()

{ }

public string Artist

{

get { return this.m _strArtist; }

set { this.m _strArtist = value; }

}

public string Title

{

get { return this.m _strTitle; }

set { this.m _strTitle = value; }

public class CTravelG uide : CBook

{

private string m _strCountry;

public CTravelG uide()

{ }

public string Country

{

get { return this m _strCountry; }

set { this m _strCountry = value ; }

}

}

Garbage Collection

• Operator new allocates memory

• When objects are no longer referenced , the

CLR performs garbage collection

• Garbage collection helps avoid memory leaks

(running out of memory because unused

memory has not been reclaimed)

• Allocation and deallocation of other resources

(database connections, file access, etc.) must be explicitly handled by programmers

• Use finalizers in conjunction with the garbage collector to release resources and memory

• Before garbage collector reclaims an object’s

memory, it calls the object’s finalizer

• Each class has only one finalizer (also called

destructor )

• Name of a destructor is the ~ character ,

followed by the class name

• Destructors do not receive any arguments

public class CTravelG uide: CBook

{

private string m _strCountry;

public CTravelG uide()

{ }

public string Country

{

get { return this m _strCountry; }

set { this m _strCountry = value ; }

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