Constants and Enumerations (Visual Basic)
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. |
Print and Display Constants
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. |