variant.tex

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%% Name:        variant.tex
%% Purpose:     wxVariant docs
%% Author:      wxWidgets Team
%% Modified by:
%% Created:     01/30/2005
%% RCS-ID:      $Id: variant.tex,v 1.13 2006/03/14 00:24:53 MR Exp $
%% Copyright:   (c) wxWidgets Team
%% License:     wxWindows license
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\section{\class{wxVariant}}\label{wxvariant}

The {\bf wxVariant} class represents a container for any type.
A variant's value can be changed at run time, possibly to a different type of value.

As standard, wxVariant can store values of type bool, char, double, long, string,
string list, time, date, void pointer, list of strings, and list of variants. However, an application can extend wxVariant's capabilities by deriving from the class \helpref{wxVariantData}{wxvariantdata} and using the wxVariantData form of the wxVariant constructor or assignment operator to assign this data to a variant. Actual values for user-defined types will need to be accessed via the wxVariantData object, unlike the case for basic data types where convenience functions such as GetLong can be used.

This class is useful for reducing the programming for certain tasks, such as an editor
for different data types, or a remote procedure call protocol.

An optional name member is associated with a wxVariant. This might be used, for example, in CORBA
or OLE automation classes, where named parameters are required.

\wxheading{Derived from}

\helpref{wxObject}{wxobject}

\wxheading{Include files}

<wx/variant.h>

\wxheading{See also}

\helpref{wxVariantData}{wxvariantdata}

\latexignore{\rtfignore{\wxheading{Members}}}

\membersection{wxVariant::wxVariant}\label{wxvariantctor}

\func{}{wxVariant}{\void}

Default constructor.

\func{}{wxVariant}{\param{const wxVariant\& }{variant}}

Copy constructor.

\func{}{wxVariant}{\param{const char*}{ value}, \param{const wxString\& }{name = ``"}}

\func{}{wxVariant}{\param{const wxString\&}{ value}, \param{const wxString\& }{name = ``"}}

Construction from a string value.

\func{}{wxVariant}{\param{char}{ value}, \param{const wxString\& }{name = ``"}}

Construction from a character value.

\func{}{wxVariant}{\param{long}{ value}, \param{const wxString\& }{name = ``"}}

Construction from an integer value. You may need to cast to (long) to
avoid confusion with other constructors (such as the bool constructor).

\func{}{wxVariant}{\param{bool}{ value}, \param{const wxString\& }{name = ``"}}

Construction from a boolean value.

\func{}{wxVariant}{\param{double}{ value}, \param{const wxString\& }{name = ``"}}

Construction from a double-precision floating point value.

\func{}{wxVariant}{\param{const wxList\&}{ value}, \param{const wxString\& }{name = ``"}}

Construction from a list of wxVariant objects. This constructor
copies {\it value}, the application is still responsible for
deleting {\it value} and its contents.

\func{}{wxVariant}{\param{void*}{ value}, \param{const wxString\& }{name = ``"}}

Construction from a void pointer.

\func{}{wxVariant}{\param{wxObject*}{ value}, \param{const wxString\& }{name = ``"}}

Construction from a wxObject pointer.

\func{}{wxVariant}{\param{wxVariantData*}{ data}, \param{const wxString\& }{name = ``"}}

Construction from user-defined data.  The variant holds onto the {\it data} pointer.

\func{}{wxVariant}{\param{wxDateTime\&}{ val}, \param{const wxString\& }{name = ``"}}

Construction from a \helpref{wxDateTime}{wxdatetime}.

\func{}{wxVariant}{\param{wxArrayString\&}{ val}, \param{const wxString\& }{name = ``"}}

Construction from an array of strings.  This constructor copies {\it value} and its contents.

\func{}{wxVariant}{\param{DATE\_STRUCT*}{ val}, \param{const wxString\& }{name = ``"}}

Construction from a odbc date value.  Represented internally by a \helpref{wxDateTime}{wxdatetime} value.

\func{}{wxVariant}{\param{TIME\_STRUCT*}{ val}, \param{const wxString\& }{name = ``"}}

Construction from a odbc time value.  Represented internally by a \helpref{wxDateTime}{wxdatetime} value.

\func{}{wxVariant}{\param{TIMESTAMP\_STRUCT*}{ val}, \param{const wxString\& }{name = ``"}}

Construction from a odbc timestamp value.  Represented internally by a \helpref{wxDateTime}{wxdatetime} value.

\membersection{wxVariant::\destruct{wxVariant}}\label{wxvariantdtor}

\func{}{\destruct{wxVariant}}{\void}

Destructor.


\membersection{wxVariant::Append}\label{wxvariantappend}

\func{void}{Append}{\param{const wxVariant\&}{ value}}

Appends a value to the list.

\membersection{wxVariant::ClearList}\label{wxvariantclearlist}

\func{void}{ClearList}{\void}

Deletes the contents of the list.


\membersection{wxVariant::Convert}\label{wxvariantconvert}

\constfunc{bool}{Convert}{\param{long*}{ value}}

\constfunc{bool}{Convert}{\param{bool*}{ value}}

\constfunc{bool}{Convert}{\param{double*}{ value}}

\constfunc{bool}{Convert}{\param{wxString*}{ value}}

\constfunc{bool}{Convert}{\param{char*}{ value}}

\constfunc{bool}{Convert}{\param{wxDateTime*}{ value}}

Retrieves and converts the value of this variant to the type that {\it value} is.


\membersection{wxVariant::GetCount}\label{wxvariantgetcount}

\constfunc{size\_t}{GetCount}{\void}

Returns the number of elements in the list.

\membersection{wxVariant::Delete}\label{wxvariantdelete}

\func{bool}{Delete}{\param{size\_t }{item}}

Deletes the zero-based {\it item} from the list.

\membersection{wxVariant::GetArrayString}\label{wxvariantgetarraystring}

\constfunc{wxArrayString}{GetArrayString}{\void}

Returns the string array value.

\membersection{wxVariant::GetBool}\label{wxvariantgetbool}

\constfunc{bool}{GetBool}{\void}

Returns the boolean value.

\membersection{wxVariant::GetChar}\label{wxvariantgetchar}

\constfunc{char}{GetChar}{\void}

Returns the character value.

\membersection{wxVariant::GetData}\label{wxvariantgetdata}

\constfunc{wxVariantData*}{GetData}{\void}

Returns a pointer to the internal variant data.

\membersection{wxVariant::GetDateTime}\label{wxvariantgetdatetime}

\constfunc{wxDateTime}{GetDateTime}{\void}

Returns the date value.

\membersection{wxVariant::GetDouble}\label{wxvariantgetdouble}

\constfunc{double}{GetDouble}{\void}

Returns the floating point value.

\membersection{wxVariant::GetLong}\label{wxvariantgetlong}

\constfunc{long}{GetLong}{\void}

Returns the integer value.

\membersection{wxVariant::GetName}\label{wxvariantgetname}

\constfunc{const wxString\&}{GetName}{\void}

Returns a constant reference to the variant name.

\membersection{wxVariant::GetString}\label{wxvariantgetstring}

\constfunc{wxString}{GetString}{\void}

Gets the string value.

\membersection{wxVariant::GetType}\label{wxvariantgettype}

\constfunc{wxString}{GetType}{\void}

Returns the value type as a string. The built-in types are: bool, char, date, double, list, long, string, stringlist, time, void*.

If the variant is null, the value type returned is the string ``null" (not the empty string).

\membersection{wxVariant::GetVoidPtr}\label{wxvariantgetvoidptr}

\constfunc{void*}{GetVoidPtr}{\void}

Gets the void pointer value.

\membersection{wxVariant::GetWxObjectPtr}\label{wxvariantgetwxobjectptr}

\constfunc{void*}{GetWxObjectPtr}{\void}

Gets the wxObject pointer value.

\membersection{wxVariant::Insert}\label{wxvariantinsert}

\func{void}{Insert}{\param{const wxVariant\&}{ value}}

Inserts a value at the front of the list.

\membersection{wxVariant::IsNull}\label{wxvariantisnull}

\constfunc{bool}{IsNull}{\void}

Returns true if there is no data associated with this variant, false if there is data.

\membersection{wxVariant::IsType}\label{wxvariantistype}

\constfunc{bool}{IsType}{\param{const wxString\&}{ type}}

Returns true if {\it type} matches the type of the variant, false otherwise.