book

Programming Visual Basic .NET, Second Edition

by Jesse Liberty

April 2003

Intermediate to advanced

560 pages

14h 4m

English

O'Reilly Media, Inc.

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About This Book
Part IPart IIPart III
Visual Basic and .NETStepchild No Longer

Examining Your First ProgramClasses and ObjectsNamespacesThe WriteLine( ) MethodComments
Using a Text EditorUsing Visual Studio .NETCreating the “Hello World” programCompiling and running “Hello World”
VB.NET Versus VB6
Working with Built-in TypesChoosing a Built-in TypeConverting Built-in Types
Default ValuesConstantsEnumerationsStrings
Unconditional Branching StatementsConditional Branching StatementsIf StatementsIf . . . Else StatementsNested If StatementsElseIfIIF: If and Only IFSelect Case Statements
Creating Loops with GotoThe Do LoopBreaking Out of a Do LoopThe For LoopControlling a For Loop Using Next
Mathematical OperatorsSimple arithmetic operators (+, -, *, /, \)Self-assignment operatorsThe modulus operator (Mod) to return remaindersThe exponentiation operator (^)String Concatenation Operators (&, +)Relational Operators
Short-Circuit EvaluationOperator Precedence
Creating Models
EncapsulationSpecialization and GeneralizationPolymorphism
Defining ClassesInstantiating ObjectsModules Are ClassesMemory Allocation: The Stack Versus the HeapCreating a Time ClassAccess Modifiers
The Get AccessorThe Set AccessorReadOnly and WriteOnly Properties
Passing Parameters by ValuePassing Parameters by ReferencePassing Reference Types by Value
Specialization and Generalization
Implementing InheritanceCalling Base Class ConstructorsShadowing Base MethodsControlling Access
Creating Polymorphic TypesCreating Polymorphic MethodsVersioning with Overridable and Overrides
Boxing Is ImplicitUnboxing Must Be Explicit
Defining a StructureNo InheritanceNo InitializationPublic Member Data?
Defining an Interface
Testing for Interface ImplementationTypeOf...Is
ArraysDeclaring ArraysThe Size of the ArrayThe ReDim KeywordUnderstanding Default ValuesAccessing Array ElementsThe For Each StatementInitializing Array ElementsThe ParamArray Keyword
Rectangular ArraysJagged Arrays
Default Properties and AssignmentIndexing on Other Values
Array ListsThe Collection ClassQueuesStacks
Creating StringsString LiteralsThe ToString( ) MethodStrings Are Immutable
Comparing StringsConcatenating StringsCopying StringsTesting for EqualityOther Useful String MethodsFinding SubstringsSplitting StringsThe StringBuilder Class
Using Match and MatchCollectionUsing Regex GroupsUsing CaptureCollection
Throwing and Catching ExceptionsThe Throw StatementThe Try and Catch StatementsHow the Call Stack WorksCreating Dedicated Catch StatementsThe Finally StatementException Class Methods and PropertiesCustom Exceptions
DelegatesUsing Delegates to Specify Methods at RuntimeShared DelegatesDelegates as Properties
Publishing and SubscribingEvents and Delegates
Creating a Simple Windows FormUsing NotepadUsing the Visual Studio .NET Designer
Creating the Basic UI FormPopulating the TreeView ControlsTreeNode objectsRecursing through the subdirectoriesGetting the files in the directoryBegin and EndUpdateHandling TreeView EventsClicking the source TreeViewClicking the target TreeViewHandling the Clear button eventImplementing the Copy Button EventGetting the selected filesSorting the list of selected filesHandling the Delete Button Event
Deployment ProjectsSetup ProjectDeployment LocationsCreating a shortcutEntries in My DocumentsShortcuts in the Start menuAdding Special FoldersOther View WindowsMaking changes to the RegistryRegistering file typesManaging the UI during SetupOther View choicesBuilding the Setup Project
Relational Databases and SQLTables, Records, and ColumnsNormalizationDeclarative Referential IntegritySQL
DataTables and DataColumnsDataRelationsRowsData AdapterDBCommand and DBConnectionThe DataAdapter Object
Populating a DataGridCustomizing the DataSetCombining Data Tables
Accessing the DataUpdating a RecordDeleting a RecordCreating New Records
Understanding Web FormsWeb Form EventsPostback versus non-postback eventsStateWeb Form Life Cycle
Setting Initial PropertiesConnecting to the Database
SOAP, WSDL, and DiscoveryServer-Side SupportClient-Side Support
Testing Your Web ServiceViewing the WSDL Contract
PE Files
Modules in the ManifestModule ManifestsOther Required Assemblies
Benefitting from Multi-Module AssembliesBuilding a Multi-Module AssemblyTesting the assemblyLoading the assembly
The End of DLL HellVersionsStrong NamesThe Global Assembly CacheBuilding a Shared AssemblyStep 1: Create a strong nameStep 2: Put the shared assembly in the GAC
AttributesIntrinsic AttributesAttribute targetsApplying attributesCustom AttributesDeclaring an attributeNaming an attributeConstructing an attributeUsing an attribute
Viewing MetaDataType DiscoveryReflecting on a TypeFinding all type membersFinding type methodsFinding particular type membersLate BindingReflection EmitDynamic invocation with InvokeMember( )Dynamic invocation with interfacesDynamic invocation with reflection emit
Application DomainsCreating and Using App DomainsMarshaling Across App Domain BoundariesUnderstanding marshaling with proxiesSpecifying the marshaling method
Context-Bound and Context-Agile ObjectsMarshaling Across Context Boundaries
Understanding Server Object TypesSpecifying a Server with an InterfaceBuilding a ServerBuilding the ClientUsing SingleCallUnderstanding RegisterWellKnownServiceTypeUnderstanding Endpoints
ThreadsStarting ThreadsJoining ThreadsSuspending ThreadsKilling Threads
Using InterlockedUsing the SyncLock StatementUsing Monitors
Race ConditionsDeadlock

Content preview from Programming Visual Basic .NET, Second Edition

Context

App domains themselves are subdivided into contexts. Contexts can be thought of as boundaries within which objects share usage rules. These usage rules include synchronization transactions, and so forth.

Context-Bound and Context-Agile Objects

Objects are either context-bound or they are context-agile. If they are context-bound, they exist in a context, and to interact with them the message must be marshaled. If they are context-agile, they act within the context of the calling object; that is, their methods execute in the context of the object that invokes the method and so marshaling is not required.

Suppose you have an object A that interacts with the database and so is marked to support transactions. This creates a context. All method calls on A occur within the context of the protection afforded by the transaction. Object A can decide to roll back the transaction, and all actions taken since the last commit are undone.

Suppose that you have another object, B, which is context-agile. Now suppose that object A passes a database reference to object B and then calls methods on B. Perhaps A and B are in a call-back relationship, in which B will do some work and then call A back with the results. Because B is context-agile, B’s method operates in the context of the calling object; thus it will be afforded the transaction protection of object A. The changes B makes to the database will be undone if A rolls back the transaction, because B’s methods execute within the context ...