Muokkaa

Jaa

Constants and Enumerations (Visual Basic)

  • Artikkeli

Visual Basic supplies a number of predefined constants and enumerations for developers. Constants store values that remain constant throughout the execution of an application. Enumerations provide a convenient way to work with sets of related constants, and to associate constant values with names.

Constants

Conditional Compilation Constants

The following table lists the predefined constants available for conditional compilation.

Constant Description
CONFIG A string that corresponds to the current setting of the Active Solution Configuration box in the Configuration Manager.
DEBUG A Boolean value that can be set in the Project Properties dialog box. By default, the Debug configuration for a project defines DEBUG. When DEBUG is defined, Debug class methods generate output to the Output window. When it is not defined, Debug class methods are not compiled and no Debug output is generated.
TARGET A string representing the output type for the project or the setting of the command-line -target option. The possible values of TARGET are:

- "winexe" for a Windows application.
- "exe" for a console application.
- "library" for a class library.
- "module" for a module.
- The -target option may be set in the Visual Studio integrated development environment. For more information, see -target (Visual Basic).
TRACE A Boolean value that can be set in the Project Properties dialog box. By default, all configurations for a project define TRACE. When TRACE is defined, Trace class methods generate output to the Output window. When it is not defined, Trace class methods are not compiled and no Trace output is generated.
VBC_VER A number representing the Visual Basic version, in major.minor format.

When you call print and display functions, you can use the following constants in your code in place of the actual values.

Constant Description
vbCrLf Carriage return/linefeed character combination.
vbCr Carriage return character.
vbLf Linefeed character.
vbNewLine Newline character.
vbNullChar Null character.
vbNullString Not the same as a zero-length string (""); used for calling external procedures.
vbObjectError Error number. User-defined error numbers should be greater than this value. For example:

Err.Raise(Number) = vbObjectError + 1000
vbTab Tab character.
vbBack Backspace character.
vbFormFeed Not used in Microsoft Windows.
vbVerticalTab Not useful in Microsoft Windows.

Enumerations

The following table lists and describes the enumerations provided by Visual Basic.

Enumeration Description
AppWinStyle Indicates the window style to use for the invoked program when calling the Shell function.
AudioPlayMode Indicates how to play sounds when calling audio methods.
BuiltInRole Indicates the type of role to check when calling the IsInRole method.
CallType Indicates the type of procedure being invoked when calling the CallByName function.
CompareMethod Indicates how to compare strings when calling comparison functions.
DateFormat Indicates how to display dates when calling the FormatDateTime function.
DateInterval Indicates how to determine and format date intervals when calling date-related functions.
DeleteDirectoryOption Specifies what should be done when a directory that is to be deleted contains files or directories.
DueDate Indicates when payments are due when calling financial methods.
FieldType Indicates whether text fields are delimited or fixed-width.
FileAttribute Indicates the file attributes to use when calling file-access functions.
FirstDayOfWeek Indicates the first day of the week to use when calling date-related functions.
FirstWeekOfYear Indicates the first week of the year to use when calling date-related functions.
MsgBoxResult Indicates which button was pressed on a message box, returned by the MsgBox function.
MsgBoxStyle Indicates which buttons to display when calling the MsgBox function.
OpenAccess Indicates how to open a file when calling file-access functions.
OpenMode Indicates how to open a file when calling file-access functions.
OpenShare Indicates how to open a file when calling file-access functions.
RecycleOption Specifies whether a file should be deleted permanently or placed in the Recycle Bin.
SearchOption Specifies whether to search all or only top-level directories.
TriState Indicates a Boolean value or whether the default should be used when calling number-formatting functions.
UICancelOption Specifies what should be done if the user clicks Cancel during an operation.
UIOption Specifies whether or not to show a progress dialog when copying, deleting, or moving files or directories.
VariantType Indicates the type of a variant object, returned by the VarType function.
VbStrConv Indicates which type of conversion to perform when calling the StrConv function.

See also