book

VB .NET Language in a Nutshell

by Steven Roman PhD, Ron Petrusha, Paul Lomax

August 2001

Intermediate to advanced

656 pages

18h 5m

English

O'Reilly Media, Inc.

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VB .NET Language in a Nutshell
Preface
Why Another VB Book?
Who This Book Is For
Readers New to Visual BasicVB and VBScript Developers New to VB .NETExisting VB .NET Developers
How This Book Is Structured
The Format of the Language Reference
Conventions Used in This Book
How to Contact Us
Acknowledgments
I. The Basics
1. Introduction
Why VB .NET?
What Is VB .NET?
Object OrientationA Common Type SystemAccess to System Services: The Framework Class LibraryA Common Runtime Environment

What Can You Do with VB .NET?
2. Variables and Data Types
VariablesVariable ScopeLocal variables: block-level and procedure-level scopeModule-level and project-level scopePrivate accessFriend accessPublic accessVariable LifetimeStatic variables
Declaring Variables and Constants
Data Types
Value and Reference TypesVB Data Types: A SummarySimple Data Types in Visual BasicBoolean data typeByte data typeChar data typeDate data typeDecimal data typeDouble data typeInteger data typeLong data typeObject data typeShort data typeSingle data typeString data typeStructure data type: user-defined typesData Type Conversion
Arrays
Definition of ArrayDimension of an ArraySize of an ArrayArrays in VB .NETRedimensioning arrays
Object Variables and Their Binding
Late Binding Versus Early Binding
The Collection Object
Parameters and Arguments
Passing ArgumentsPassing ObjectsOptional ArgumentsParamArray
3. Introduction to Object-Oriented Programming
Why Learn Object-Oriented Techniques?
Principles of Object-Oriented Programming
AbstractionEncapsulationInterfaces
Classes and Objects
Class Modules in VB .NETClass MembersThe Public Interface of a VB .NET ClassObjectsPropertiesInstance and Shared MembersClass ConstructorsFinalize, Dispose, and Garbage Collection
Inheritance
Permission to InheritOverridingRules of InheritanceMyBase, MyClass, and Me
Interfaces, Abstract Members, and Classes
Interfaces Revisited
Polymorphism and Overloading
OverloadingPolymorphism
Scope and Accessibility in Class Modules
4. The .NET Framework: General Concepts
Namespaces
Common Language Runtime (CLR), Managed Code, and Managed Data
Managed Execution
Assemblies
Assemblies and VB .NET
5. The .NET Framework Class Library
The System NamespaceData Type ConversionThe Array ClassThe Math ClassThe String Class
Other Namespaces
System.CollectionsSystem.DataSystem.IOSystem.Text.RegularExpressionsSystem.Windows.Forms
6. Delegates and Events
DelegatesUsing a Delegate to Call a MethodUsing a Delegate as a Function Pointer
Events and Event Binding
Control-Related EventsWithEventsAddHandler
7. Error Handling in VB .NET
Error Detection and Error Handling
Runtime Error Handling
Unstructured Error HandlingThe Err objectDealing with runtime errorsIn-line error handlingCentralized error handlingNo enabled error-handlerStructured Exception HandlingTry...Catch...FinallyException classes
Dealing with Logical Errors
Detecting Logical ErrorsWhere to Handle a Logical ErrorHandling the error on the spotHandling the error in the offending procedure’s error handlerPassing the error to the calling procedure
Error Constants
II. Reference
8. The Language Reference
#Const Directive
#If...Then...#Else Directive
#Region...#End Region Directive
Abs Function
Acos Function
AddHandler Statement
AddressOf Operator
AppActivate Procedure
Application Class
Application.CompanyName Property
Application.DoEvents Method
Application.ExecutablePath Property
Application.ProductName Property
Application.ProductVersion Property
Array Class
Array.BinarySearch Method
Array.Copy Method
Array.IndexOf Method
Array.LastIndexOf Method
Array.Reverse Method
Array.Sort Method
Asc, AscW Functions
Asin Function
Atan Function
Atan2 Function
Beep Procedure
Call Statement
CallByName Function
CBool Function
CByte Function
CChar Function
CDate Function
CDbl Function
CDec Function
Ceiling Function
ChDir Procedure
ChDrive Procedure
Choose Function
Chr, ChrW Functions
CInt Function
Class Statement
Clipboard Class
Clipboard.GetDataObject Method
Clipboard.SetDataObject Method
CLng Function
CObj Function
Collection Class
Collection.Add Method
Collection.Count Property
Collection.Item Method
Collection.Remove Method
ColorDialog Class
Command Function
Const Statement
Cos Function
Cosh Function
CreateObject Function
CShort Function
CSng Function
CStr Function
CType Function
CurDir Function
DateAdd Function
DateDiff Function
DatePart Function
DateSerial Function
DateString Property
DateValue Function
Day Function
DDB Function
Debug Class
Debug.Assert Method
Debug.AutoFlush Property
Debug.Close Method
Debug.Flush Method
Debug.Indent Method
Debug.IndentLevel Property
Debug.IndentSize Property
Debug.Listeners Property
Debug.Unindent Method
Debug.Write Method
Debug.WriteIf Method
Debug.WriteLine Method
Debug.WriteLineIf Method
Declare Statement
Delegate Statement
DeleteSetting Procedure
Dim Statement
Dir Function
Directory Class
Directory.CreateDirectory Method
Directory.Delete Method
Directory.Exists Method
Directory.GetCreationTime Method
Directory.GetDirectories Method
Directory.GetDirectoryRoot Method
Directory.GetFiles Method
Directory.GetFileSystemEntries Method
Directory.GetLogicalDrives Method
Directory.GetParent Method
Directory.Move Method
Do...Loop Statement
E Field
End→Statement
Enum Statement
Environ Function
EOF Function
Erase Statement
Erl Property
Err Object
Err.Clear Method
Err.Description Property
Err.GetException Method
Err.HelpContext Property
Err.HelpFile Property
Err.LastDLLError Property
Err.Number Property
Err.Raise Method
Err.Source Property
Error Statement
ErrorToString Function
Event Statement
Exception Class
Exit Statement
Exp Function
File Class
File.Exists Method
FileAttr Function
FileClose Procedure
FileCopy Procedure
FileDateTime Function
FileGet, FileGetObject Procedures
FileLen Function
FileOpen Procedure
FilePut, FilePutObject Procedures
FileWidth Procedure
Filter Function
Fix Function
Floor Function
FontDialog Class
For...Next Statement
For Each...Next Statement
Format Function
FormatCurrency, FormatNumber, FormatPercent Functions
FormatDateTime Function
FreeFile Function
Friend Keyword
Function Statement
FV Function
Get Statement
GetAllSettings Function
GetAttr Function
GetChar Function
GetObject Function
GetSetting Function
GetTimer Function
GoTo Statement
Handles Keyword
Hashtable Class
Hashtable.Add Method
Hashtable.Clear Method
Hashtable.ContainsKey Method
Hashtable.ContainsValue Method
Hashtable.CopyTo Method
Hashtable.Count Property
Hashtable.Item Property
Hashtable.Keys Property
Hashtable.Remove Method
Hashtable.Values Property
Hex Function
Hour Function
IDataObject Interface
IDataObject.GetData Method
IDataObject.GetDataPresent Method
IDataObject.GetFormats Method
IEEERemainder Function
If...Then...Else Statement
IIf Function
Implements Keyword
Implements Statement
Imports Statement
Inherits Statement
Input Procedure
InputBox Function
InputString Function
InStr Function
InStrRev Function
Int Function
Interface Statement
IPmt Function
IRR Function
Is Operator
IsArray Function
IsDate Function
IsDBNull Function
IsError Function
IsNothing Function
IsNumeric Function
IsReference Function
Join Function
Kill Procedure
LBound Function
LCase Function
Left Function
Len Function
Like Operator
LineInput Function
Loc Function
Lock Procedure
LOF Function
Log Function
Log10 Function
LTrim Function
Max Function
Me Operator
Mid Function
Mid Statement
Min Function
Minute Function
MIRR Function
MkDir Procedure
Mod Operator
Module...End Module Statement
Month Function
MonthName Function
MsgBox Function
MyBase Keyword
MyClass Keyword
Namespace Statement
Now Property
NPer Function
NPV Function
Oct Function
On Error Statement
OpenFileDialog Class
Option Compare Statement
Option Explicit Statement
Option Strict Statement
Partition Function
Pi Field
Pmt Function
Pow Function
PPmt Function
Print, PrintLine Procedures
Private Statement
Property Statement
Protected Keyword
Public Statement
PV Function
QBColor Function
Queue Class
Queue.Clear Method
Queue.Contains Method
Queue.CopyTo Method
Queue.Count Property
Queue.Dequeue Method
Queue.Enqueue Method
Queue.Peek Method
Queue.ToArray Method
RaiseEvent Statement
Randomize Procedure
Rate Function
ReDim Statement
Rem Statement
Rename Procedure
Replace Function
Reset Procedure
Resume Statement
Return Statement
RGB Function
Right Function
RmDir Procedure
Rnd Function
Round Function
RTrim Function
SaveFileDialog Class
SaveSetting Procedure
ScriptEngine Function
ScriptEngineBuildVersion Function
ScriptEngineMajorVersion Function
ScriptEngineMinorVersion Function
Second Function
Seek Function
Seek Procedure
Select Case Statement
Send, SendWait Methods
Set Statement
SetAttr Procedure
Shadows Keyword
Shell Function
Sign Function
Sin Function
Sinh Function
SLN Function
Space Function
Spc Function
Split Function
Sqrt Function
Stack Class
Stack.Clear Method
Stack.Contains Method
Stack.CopyTo Method
Stack.Count Property
Stack.Peek Method
Stack.Pop Method
Stack.Push Method
Stack.ToArray Method
Static Statement
Stop Statement
Str Function
StrComp Function
StrConv Function
StrDup Function
StrReverse Function
Structure...End Structure Statement
Sub Statement
Switch Function
SYD Function
SyncLock Statement
SystemTypeName Function
Tab Function
Tan Function
Tanh Function
Throw Statement
TimeOfDay Property
Timer Property
TimeSerial Function
TimeString Property
TimeValue Function
Today Property
Trim Function
Try...Catch...Finally Statement
TypeName Function
UBound Function
UCase Function
Unlock Procedure
Val Function
ValDec Function
VarType Function
VbTypeName Function
Weekday Function
WeekdayName Function
While...End While Statement
With Statement
WithEvents Keyword
Write Procedure
WriteLine Procedure
Year Function
III. Appendixes
A. What’s New and Different in VB .NET
Language Changes for VB .NETData TypesStringsInteger/Long data type changesVariant data typeOther data type changesVariables and Their DeclarationVariable declarationVariable initializationVariable scope changesArrays and array declarationsStructure/user-defined type declarationsBoolean and Bitwise OperatorsChanges Related to ProceduresCalling a procedureDefault Method of Passing ArgumentsOptional argumentsReturn statementPassing property parameters in proceduresParamArray parametersMiscellaneous Language ChangesLine numbersOn GoToWhileGoSub and Return statements
Changes to Programming Elements
ConstantsString FunctionsEmptinessGraphical FunctionalityMathematical FunctionalityDiagnosticsMiscellaneous
Obsolete Programming Elements
Structured Exception Handling
Changes in Object-Orientation
InheritanceOverloadingObject CreationPropertiesDefault propertiesProperty declarations
B. Language Elements by Category
Array Handling
Clipboard
Collection Objects
Common Dialogs
Conditional Compilation
Conversion
Data Type ConversionOther Conversion
Date and Time
Debugging
Declaration
Error Handling
Filesystem
Financial
IDataObject Interface
Information
Input/Output
Integrated Development Environment
Interaction
Mathematics
Program Structure and Flow
Programming
Object ProgrammingMiscellaneous Programming
Registry
String Manipulation
C. Operators
Arithmetic Operators
Assignment Operators
Concatenation Operators
Comparison Operators
The Is OperatorThe Like Operator
Logical and Bitwise Operators
Operator Precedence
D. Constants and Enumerations
Visual Basic Intrinsic Constants
ControlChars Class
Visual Basic Enumerations
AppWinStyle EnumerationCallType EnumerationCompareMethod EnumerationDateFormat EnumerationDateInterval EnumerationDueDate EnumerationFileAttribute EnumerationFirstDayOfWeek EnumerationFirstWeekOfYear EnumerationMsgBoxResult EnumerationMsgBoxStyle EnumerationOpenAccess EnumerationOpenMode EnumerationOpenModeTypes EnumerationOpenShare EnumerationPrintFlags EnumerationTriState EnumerationVariantType EnumerationVbStrConv Enumeration
E. The VB .NET Command-Line Compiler
Compiler Basics
Command-Line Switches
Output Filename and File TypeInput FilesResourcesCode GenerationDebuggingErrors and WarningsLanguageMiscellaneousAdvanced
Using a Response File
F. VB 6 Language Elements Not Supported by VB .NET
Index
Colophon

Content preview from VB .NET Language in a Nutshell

Name

Error Statement

Syntax

Error [errornumber]

errornumber

Use: Optional

Data Type: Long

Any valid error code

Description

Raises an error

Rules at a glance

The Error statement is included only for backward compatibility; instead, if you’re using standard Visual Basic error handling, you should use the Err.Raise method and the Err object. Otherwise, you should use structured exception handling with the Try...Catch construct.

Programming Tips and Gotchas

The Error statement has been a “compatibility” statement for several versions of Visual Basic. Interestingly, it managed to survive the general purge of outdated language elements. Despite its persistence, we still recommend that its use be strictly avoided.