Versioning in C#

Printer QR in C# Versioning
Versioning
Quick Response Code Maker In C#.NET
Using Barcode encoder for VS .NET Control to generate, create QR Code ISO/IEC18004 image in Visual Studio .NET applications.
Changing or removing a particular interface member signature is obviously a code-breaking change, as any call to that member will no longer compile without modification The same is true when changing public or protected member signatures on a class However, unlike with classes, adding members to an interface could also prevent code from compiling without additional changes The problem is that any class implementing the interface must do so entirely, and implementations for all members must be provided With new interface members, the compiler will require that developers add new interface members to the class implementing the interface The creation of IDistributedSettingsProvider in Listing 712 serves as a good example of extending an interface in a version-compatible way Imagine that at first, only the ISettingsProvider interface is defined (as it was in Listing 76) In the next version, however, it is determined that permachine settings are required To enable this, the IDistributedSettingsProvider interface is created, and it derives from ISettingsProvider
Painting Barcode In C#.NET
Using Barcode creation for .NET framework Control to generate, create bar code image in .NET applications.
Listing 712: Deriving One Interface from Another
Printing QR Code ISO/IEC18004 In VS .NET
Using Barcode generation for ASP.NET Control to generate, create QR Code JIS X 0510 image in ASP.NET applications.
interface IDistributedSettingsProvider : ISettingsProvider { /// <summary> /// Get the settings for a particular machine /// </summary> /// <param name="machineName"> /// The machine name the setting is related to</param> /// <param name="name">The name of the setting</param> /// <param name="defaultValue"> /// The value returned if the setting is not found</param> /// <returns>The specified setting</returns> string GetSetting( string machineName, string name, string defaultValue); /// <summary> /// Set the settings for a particular machine /// </summary> /// <param name="machineName"> /// The machine name the setting is related to</param> /// <param name="name">The name of the setting</param> /// <param name="value">The value to be persisted</param> /// <returns>The specified setting</returns> void SetSetting( string machineName, string name, string value); }
Creating QR Code In .NET
Using Barcode maker for .NET Control to generate, create QR image in .NET applications.
7: Interfaces
Denso QR Bar Code Generator In Visual Basic .NET
Using Barcode drawer for .NET framework Control to generate, create QR Code image in .NET applications.
The important factor is that programmers with classes that implement ISettingsProvider can choose to upgrade the implementation to include IDistributedSettingsProvider, or they can ignore it If instead of creating a new interface, the machine-related methods are added to ISettingsProvider, then classes implementing this interface will no longer successfully compile with the new interface definition, and instead a version-breaking change will occur Changing interfaces during the development phase is obviously acceptable, although perhaps laborious if implemented extensively However, once an interface is released, it should not be changed Instead, a second interface should be created, possibly deriving from the original interface (Listing 712 includes XML comments describing the interface members, as discussed further in 9)
Create Barcode In C#
Using Barcode generation for .NET Control to generate, create bar code image in .NET framework applications.
Interfaces Compared with Classes
Print Bar Code In Visual C#.NET
Using Barcode printer for Visual Studio .NET Control to generate, create bar code image in VS .NET applications.
Interfaces introduce another category of data types (They are one of the few categories of types that don t extend SystemObject2) Unlike classes, however, interfaces can never be instantiated An interface instance is accessible only via a reference to an object that implements the interface It is not possible to use the new operator with an interface; therefore, interfaces cannot contain any constructors or finalizers Furthermore, static members are not allowed on interfaces Interfaces are closer to abstract classes, sharing such features as the lack of instantiation capability Table 71 lists additional comparisons
Make Code 3 Of 9 In Visual C#.NET
Using Barcode creation for VS .NET Control to generate, create Code-39 image in .NET applications.
TABLE 71: Comparing Abstract Classes and Interfaces
Code 128C Generation In C#.NET
Using Barcode encoder for .NET framework Control to generate, create Code 128A image in Visual Studio .NET applications.
Abstract Classes
Data Matrix 2d Barcode Generator In C#.NET
Using Barcode printer for VS .NET Control to generate, create DataMatrix image in VS .NET applications.
Interfaces
Print ANSI/AIM Code 39 In VS .NET
Using Barcode generation for .NET framework Control to generate, create Code-39 image in VS .NET applications.
Cannot be instantiated independently from their derived classes Abstract class constructors are called only by their derived classes
Data Matrix 2d Barcode Scanner In VS .NET
Using Barcode scanner for .NET framework Control to read, scan read, scan image in VS .NET applications.
Cannot be instantiated
Creating GS1-128 In .NET
Using Barcode encoder for .NET Control to generate, create USS-128 image in VS .NET applications.
2 The others being pointer types and type parameter types
Generate Code 39 Full ASCII In Java
Using Barcode drawer for Java Control to generate, create Code-39 image in Java applications.
Summary
EAN-13 Drawer In VS .NET
Using Barcode generation for ASP.NET Control to generate, create GS1 - 13 image in ASP.NET applications.
TABLE 71: Comparing Abstract Classes and Interfaces (Continued)
Draw Bar Code In .NET Framework
Using Barcode generator for ASP.NET Control to generate, create bar code image in ASP.NET applications.
Abstract Classes
Bar Code Reader In .NET
Using Barcode recognizer for .NET framework Control to read, scan read, scan image in VS .NET applications.
Interfaces
Draw Bar Code In Java
Using Barcode maker for Java Control to generate, create barcode image in Java applications.
Define abstract member signatures that base classes must implement
Making Bar Code In .NET
Using Barcode encoder for ASP.NET Control to generate, create bar code image in ASP.NET applications.
Implementation of all members of the interface occurs in the base class It is not possible to implement only some members within the implementing class Extending interfaces with additional members breaks the version compatibility
GS1 - 12 Maker In Java
Using Barcode encoder for Java Control to generate, create UCC - 12 image in Java applications.
Are more extensible than interfaces, without breaking any version compatibility With abstract classes, it is possible to add additional nonabstract members that all derived classes can inherit Can include data stored in fields
Cannot store any data Fields can be specified only on the deriving classes The workaround for this is to define properties, but without implementation All members are automatically virtual and cannot include any implementation Although no default implementation can appear, classes implementing interfaces can continue to derive from one another
Allow for (virtual) members that have implementation and, therefore, provide a default implementation of a member to the deriving class Deriving from an abstract class uses up a subclass s one and only base class option
Given that abstract classes and interfaces have their own sets of advantages and disadvantages, you must make a cost-benefit decision based on the comparisons in Table 71 in order to make the right choice