book

Visual Basic Design Patterns: VB 6.0 and VB.NET

by James W. Cooper

November 2001

Intermediate to advanced

512 pages

9h 10m

English

Addison-Wesley Professional

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Defining Design PatternsThe Learning ProcessStudying Design PatternsNotes on Object-Oriented ApproachesVB Design PatternsHow This Book Is Organized
InheritanceInterfacesCompositionAnnotationWithClass UML DiagramsVisual Basic Project Files
A Simple Temperature Conversion ProgramBuilding a Temperature ClassConverting to KelvinPutting the Decisions into the Temperature ClassUsing Classes for Format and Value ConversionHandling Unreasonable ValuesA String Tokenizer ClassClasses as ObjectsClass ContainmentClass InitializationClasses and PropertiesAnother Interface Example—The VoltmeterA vbFile ClassProgramming Style in Visual BasicSummary
Building VB ObjectsCreating Instances of ObjectsA VB Measurement ProgramMethods Inside ObjectsVariablesPassing Arguments by Reference and by ValueObject-Oriented Jargon
A Highlighted Text FieldResizing a User ControlTesting Your HiText ControlsAdding Properties and Methods to User ControlsCompiling a User ControlSummaryPrograms on the CD-ROM
InterfacesAn Investment SimulatorWriting the SimulatorIndicators for Using an InterfaceReusing Common MethodsHidden InterfacesSummaryPrograms on the CD-ROM

Syntax Differences in VB.NETImproved Function SyntaxVariable Declarations and ScopingObjects in VB.NETCompiler OptionsNumbers in VB.NETProperties in VB6 and VB.NETShorthand Equals SyntaxManaged Languages and Garbage CollectionClasses in VB.NETBuilding a VB7 ApplicationThe Simplest Window Program in VB.NETInheritanceConstructorsDrawing and Graphics in VB.NETTooltips and CursorsOverloadingInheritanceNamespacesCreating a Square from a RectanglePublic, Private, and ProtectedOverriding Methods in Derived ClassesOverloading and ShadowingOverriding Windows ControlsInterfacesSummaryPrograms on the CD-ROM
ArraysCollection ObjectsArrayListsHashtablesSortedListsExceptionsMultiple ExceptionsThrowing ExceptionsFile HandlingThe File ObjectReading a Text FileWriting a Text FileExceptions in File HandlingTesting for End of FileThe FileInfo ClassA vbFile ClassPrograms on the CD-ROM
How a Simple Factory WorksSample CodeThe Two Derived ClassesBuilding the Simple FactoryUsing the FactoryWriting the Factory Pattern in VB.NETFactory Patterns in Math ComputationPrograms on the CD-ROM
The Swimmer ClassThe Events ClassesStraight SeedingCircle SeedingOur Seeding ProgramOther FactoriesThe Seeding Program in VB7When to Use a Factory MethodPrograms on the CD-ROM
A GardenMaker FactoryHow the User Interface WorksCreating an Abstract Factory Using VB7The PictureBoxHandling the RadioButton and Button EventsAdding More ClassesConsequences of Abstract FactoryPrograms on the CD-ROM
Creating Singleton Using a Static MethodCatching the ErrorProviding a Global Point of Access to a SingletonThe MSComm Control as a SingletonAvailable PortsWriting a Singleton in VB.NETUsing a Private ConstructorError Handling in Our SingletonA VB.NET SpoolDemo ProgramThe Global Point of AccessOther Consequences of the Singleton PatternPrograms on the CD-ROM
An Investment TrackerCalling the BuildersThe List Box BuilderThe Check Box BuilderWriting a Builder in VB.NETThe Stock FactoryThe CheckChoice ClassThe ListboxChoice ClassUsing the Items Collection in the ListBox ControlThe Final ChoiceConsequences of the Builder PatternPrograms on the CD-ROM
Cloning in Visual Basic 6Using the PrototypeUsing the Prototype PatternAdditional Methods in SubclassesDissimilar Classes with the Same InterfacePrototype ManagersWriting a Prototype in VB7Consequences of the Prototype PatternPrograms on the CD-ROMSummary of Creational Patterns
Moving Data between ListsUsing the MSFlexGridUsing a TreeViewThe Object AdapterUsing Adapters in VB7TreeView Adapters for VB.NETAdapting a DataGridThe Class AdapterTwo-Way AdaptersObject versus Class Adapters in VB.NETPluggable AdaptersAdapters in VBPrograms on the CD-ROM
The visList ClassesThe Class DiagramExtending the BridgeActiveX Controls as BridgesThe Bridge Pattern in VB.NETThe ListBox VisList ClassThe Grid VisList ClassLoading the DataChanging the Data Side of the BridgeConsequences of the Bridge PatternPrograms on the CD-ROM
An Implementation of a CompositeComputing SalariesThe Employee ClassesThe Subords ClassThe Boss ClassBuilding the Employee TreeSelf-PromotionDoubly Linked ListsConsequences of the Composite PatternA Simple CompositeComposites in VBThe Composite in VB.NETThe EnumeratorMultiple Boss ConstructorsOther Implementation IssuesPrograms on the CD-ROM
Decorating a CoolButtonUsing a DecoratorUsing ActiveX Controls as DecoratorsA Decorator in VB.NETNonvisual DecoratorsDecorators, Adapters, and CompositesConsequences of the Decorator PatternPrograms on the CD-ROM
What Is a Database?Getting Data Out of DatabasesKinds of DatabasesODBCMicrosoft Database Connection StrategiesDatabase StructureThe DBase ClassBuilding the Façade ClassesThe Stores ClassBuilding the Stores and Foods TablesBuilding the Price TableBuilding the Price QuerySummary of the Façade PatternADO Database Access in VB6The ADO ConnectionAdding and Seeking Rows Table RowsUsing the ADO ExtensionsThe ADO DBase ClassDatabase Access in VB.NETUsing ADO.NETConnecting to a DatabaseReading Data from a Database TableExecuting a QueryDeleting the Contents of a TableAdding Rows to Database Tables Using ADO.NETMaking the VB.NET ADO FaçadeThe DBTable ClassCreating Classes for Each TableStoring the PricesLoading the Database TablesThe Final ApplicationWhat Constitutes the Façade?Consequences of the FaçadePrograms on the CD-ROM
DiscussionExample CodeThe Class DiagramSelecting a FolderWriting a Flyweight Folder in VB.NETFlyweight Uses in VBSharable ObjectsCopy-on-Write ObjectsPrograms on the CD-ROM
Sample CodeWriting a Proxy in VB.NetProxies in VBCopy-on-WriteComparison with Related PatternsPrograms on the CD-ROMSummary of Structural Patterns
ApplicabilitySample CodeThe List BoxesProgramming a Help SystemReceiving the Help CommandA Chain or a Tree?Chain of Responsibility in VB.NETKinds of RequestsExamples in VBConsequences of the Chain of ResponsibilityPrograms on the CD-ROM
MotivationCommand ObjectsBuilding Command ObjectsArrays of CommandsConsequences of the Command PatternProviding UndoThe Command Pattern in VB.NETThe CommandHolder InterfaceHandling Undo Commands in VB.NETThe Command Pattern in the VB LanguagePrograms on the CD-ROM
MotivationApplicabilityA Simple Report ExampleInterpreting the LanguageObjects Used in ParsingReducing the Parsed StackImplementing the Interpreter PatternThe Syntax TreeBuilding an Interpreter in VB6The Parse ObjectsConsequences of the Interpreter PatternPrograms on the CD-ROM
MotivationSample VB6 CodeFetching an IteratorFiltered IteratorsThe Filtered IteratorIterators in VB.NETConsequences of the Iterator PatternPrograms on the CD-ROM
An Example SystemInteractions between ControlsSample CodeInitialization of the SystemMediators and Command ObjectsThe Mediator in VB.NetInitializationHandling the Events for the New ControlsConsequences of the Mediator PatternSingle Interface MediatorsImplementation IssuesPrograms on the CD-ROM
MotivationImplementationSample CodeA Cautionary NoteCommand Objects in the User InterfaceHandling Mouse and Paint EventsWriting a Memento in VB.NETConsequences of the MementoPrograms on the CD-ROM
Watching Colors ChangeWriting an Observer in VB.NETThe Message to the MediaConsequences of the Observer PatternPrograms on the CD-ROM
Sample CodeSwitching between StatesHow the Mediator Interacts with the State ManagerHandling the Fill StateHandling the Undo ListFilling Circles in VB6A State Pattern in VB.NETMediators and the God ClassConsequences of the State PatternState TransitionsPrograms on the CD-ROM
MotivationSample CodeThe ContextThe Program CommandsThe Line and Bar Graph StrategiesDrawing Plots in VBA Strategy Pattern in VB.NETConsequences of the Strategy PatternPrograms on the CD-ROM
MotivationKinds of Methods in a Template ClassSample CodeDrawing a Standard TriangleDrawing an Isosceles TriangleThe Triangle Drawing ProgramTemplates and CallbacksSummary and ConsequencesPrograms on the CD-ROM
MotivationWhen to Use the Visitor PatternSample CodeVisiting the ClassesVisiting Several ClassesBosses Are Employees, TooCatch-All Operations with VisitorsDouble DispatchingWhy Are We Doing This?Traversing a Series of ClassesWriting a Visitor in VB6Consequences of the Visitor PatternPrograms on the CD-ROM

Content preview from Visual Basic Design Patterns: VB 6.0 and VB.NET

Chapter 17. The Composite Pattern

Frequently programmers develop systems in which a component may be either an individual object or a collection of objects. The Composite pattern is designed to accommodate both cases. You can use the Composite to build part-whole hierarchies or to construct data representations of trees. In summary, a composite is a collection of objects, any one of which may be either a composite or just a primitive object. In tree nomenclature, some objects may be nodes with additional branches and some may be leaves.

The problem that develops is the dichotomy between having a single, simple interface to access all the objects in a composite and the ability to distinguish between nodes and leaves. Nodes have children and can ...