make barcode with vb.net Static and Instance Members | in Visual C#

Generate ANSI/AIM Code 128 in Visual C# Static and Instance Members |

Static and Instance Members |
Draw Code 128A In Visual C#.NET
Using Barcode creation for Visual Studio .NET Control to generate, create Code 128C image in .NET applications.
www.OnBarcode.com
Decoding Code 128 In C#
Using Barcode scanner for Visual Studio .NET Control to read, scan read, scan image in .NET applications.
www.OnBarcode.com
For this example, the Cat class has been stripped to its absolute essentials. The complete listing is shown in Example 7-6. An analysis follows the example.
EAN 128 Printer In Visual C#.NET
Using Barcode creator for .NET framework Control to generate, create EAN / UCC - 13 image in VS .NET applications.
www.OnBarcode.com
Code 128B Maker In Visual C#
Using Barcode generator for .NET framework Control to generate, create Code 128 Code Set C image in .NET applications.
www.OnBarcode.com
using using using using System; System.Collections.Generic; System.Linq; System.Text;
Data Matrix 2d Barcode Encoder In C#
Using Barcode creation for .NET framework Control to generate, create ECC200 image in .NET applications.
www.OnBarcode.com
Draw Barcode In C#
Using Barcode printer for .NET Control to generate, create Barcode image in VS .NET applications.
www.OnBarcode.com
namespace Example_7_6_ _ _ _Static_Fields { // declare a Cat class, stripped down public class Cat { // a private static member to keep track of how many Cat objects // have been created private static int instances = 0; private int weight; private String name; // cat constructor, increments the count of Cats public Cat( String name, int weight ) { instances++; this.name = name; this.weight = weight; } // Static method to retrieve the current number of Cats public static void HowManyCats( ) { Console.WriteLine( "{0} cats adopted", instances ); } public void TellWeight( ) { Console.WriteLine( "{0} is {1} pounds", name, weight ); } } class Tester { public void Run( ) { Cat.HowManyCats( ); Cat frisky = new Cat( "Frisky", 5 ); frisky.TellWeight( ); Cat.HowManyCats( ); Cat whiskers = new Cat( "Whiskers", 7 );
Code 39 Full ASCII Drawer In Visual C#.NET
Using Barcode generation for Visual Studio .NET Control to generate, create Code 3/9 image in .NET framework applications.
www.OnBarcode.com
USD8 Creator In Visual C#.NET
Using Barcode drawer for .NET Control to generate, create Code 11 image in .NET framework applications.
www.OnBarcode.com
|
Code128 Encoder In Visual Studio .NET
Using Barcode drawer for Visual Studio .NET Control to generate, create USS Code 128 image in Visual Studio .NET applications.
www.OnBarcode.com
Code 128A Creator In Java
Using Barcode creator for Android Control to generate, create Code 128 Code Set C image in Android applications.
www.OnBarcode.com
7: Classes and Objects
Encode USS Code 39 In None
Using Barcode encoder for Font Control to generate, create Code 3/9 image in Font applications.
www.OnBarcode.com
Scanning Barcode In .NET Framework
Using Barcode Control SDK for ASP.NET Control to generate, create, read, scan barcode image in ASP.NET applications.
www.OnBarcode.com
whiskers.TellWeight( ); Cat.HowManyCats( ); } static void Main( ) { Tester t = new Tester( ); t.Run( ); } } }
Scanning Code 39 Full ASCII In Java
Using Barcode reader for Java Control to read, scan read, scan image in Java applications.
www.OnBarcode.com
Encoding UPC Code In Java
Using Barcode generator for Java Control to generate, create UPC A image in Java applications.
www.OnBarcode.com
Here is the output:
Printing QR Code In None
Using Barcode printer for Office Word Control to generate, create QR Code JIS X 0510 image in Office Word applications.
www.OnBarcode.com
Create PDF 417 In None
Using Barcode drawer for Online Control to generate, create PDF 417 image in Online applications.
www.OnBarcode.com
0 cats adopted Frisky is 5 pounds 1 cats adopted Whiskers is 7 pounds 2 cats adopted
Read Barcode In None
Using Barcode recognizer for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
Read ANSI/AIM Code 39 In None
Using Barcode reader for Software Control to read, scan read, scan image in Software applications.
www.OnBarcode.com
The Cat class begins by defining a static member variable, instances, that is initialized to zero. When you initialize a static variable, the initialization always takes place before any reference is made to that variable. This static member field will keep track of the number of Cat objects created. Each time the constructor runs (creating a new object), the instances field is incremented. The Cat class also defines two instance fields: name and weight. These track the name and weight of each individual Cat object. The Cat class defines two methods: HowManyCats( ) and TellWeight( ). HowManyCats( ) is static. The number of Cats is not an attribute of any given Cat; it is an attribute of the entire class. That is, there s only one instance of the instances variable for all Cat objects. TellWeight( ) is an instance method. The name and weight of each cat is unique for each instance each Cat has its own instance of the name and weight variables. The Main( ) method accesses the static HowManyCats( ) method directly, through the class name:
PDF417 Scanner In .NET
Using Barcode reader for .NET Control to read, scan read, scan image in Visual Studio .NET applications.
www.OnBarcode.com
ECC200 Generator In Java
Using Barcode drawer for Java Control to generate, create Data Matrix image in Java applications.
www.OnBarcode.com
Cat.HowManyCats( );
Main( ) then creates an instance of Cat and accesses the instance method, TellWeight( ), through the instance of Cat:
Cat frisky = new Cat( ) frisky.TellWeight( );
Each time a new Cat is created, HowManyCats( ) reports the increase.
Static and Instance Members |
Finalizing Objects
Unlike many other programming languages (C, C++, Pascal, and so on), C# provides garbage collection. Your objects are destroyed after you are done with them although not immediately after; they re destroyed when the garbage collection process runs, which is determined by the system. You do not need to worry about cleaning up after your objects unless you use unmanaged or scarce resources. An unmanaged resource is an operating-system feature outside the .NET Framework, such as a connection to a database. A scarce resource is a resource that you have in limited quantity, perhaps because of licensing limitations or limited bandwidth. Graphics resources, such as fonts and brushes, are considered scarce because of the way the operating system works. If you do control an unmanaged resource, you need to explicitly free that resource when you are done with it. Typically, you ll manage this by implementing the IDisposable interface. (You will learn more about interfaces in 13.) The IDisposable interface requires you to create a method named Dispose( ), which will be called by your clients. If you provide a Dispose( ) method, you should stop the garbage collector from calling your object s destructor. To stop the garbage collector, call the static method GC.SuppressFinalize( ), passing in the this reference for your object. Your finalizer can then call your Dispose( ) method. Thus, you might write:
using System; class Testing : IDisposable { bool is_disposed = false; protected virtual void Dispose( bool disposing ) { if ( !is_disposed ) // only dispose once! { if ( disposing ) { // OK to reference other objects } // perform cleanup for this object Console.WriteLine( "Disposing..." ); } this.is_disposed = true; } public void Dispose( ) { Dispose( true ); GC.SuppressFinalize( this ); } }
|
Copyright © OnBarcode.com . All rights reserved.