@class wxVariant
@wxheader{variant.h}
- The @b 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.
+ The @b 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, wxChar, double, long,
- string,
- string list, time, date, void pointer, list of strings, and list of variants.
+ 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 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
+ class 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
wxVariant::GetLong can be used.
- Pointers to any wxObject derived class can also easily be stored
- in a wxVariant. wxVariant will then use wxWidgets' built-in RTTI system to set
- the
- type name (returned by wxVariant::GetType) and to perform
- type-safety checks at runtime.
+ Pointers to any wxObject derived class can also easily be stored in a wxVariant.
+ wxVariant will then use wxWidgets' built-in RTTI system to set the type name
+ (returned by wxVariant::GetType) and to perform type-safety checks at runtime.
- 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.
+ 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.
+ 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.
Note that as of wxWidgets 2.7.1, wxVariant is @ref overview_trefcount
"reference counted".
Additionally, the convenience macros @b DECLARE_VARIANT_OBJECT and
@b IMPLEMENT_VARIANT_OBJECT were added so that adding (limited) support
- for conversion to and from wxVariant can be very easily implemented without
- modifying
- either wxVariant or the class to be stored by wxVariant. Since assignment
- operators
- cannot be declared outside the class, the shift left operators are used like
- this:
+ for conversion to and from wxVariant can be very easily implemented
+ without modifying either wxVariant or the class to be stored by wxVariant.
+ Since assignment operators cannot be declared outside the class, the shift
+ left operators are used like this:
@code
// in the header file
- DECLARE_VARIANT_OBJECT(MyClass)
+ DECLARE_VARIANT_OBJECT(MyClass)
- // in the implementation file
- IMPLEMENT_VARIANT_OBJECT(MyClass)
+ // in the implementation file
+ IMPLEMENT_VARIANT_OBJECT(MyClass)
- // in the user code
- wxVariant variant;
- MyClass value;
- variant value;
+ // in the user code
+ wxVariant variant;
+ MyClass value;
+ variant << value;
- // or
- value variant;
+ // or
+ value << variant;
@endcode
For this to work, MyClass must derive from wxObject, implement
Clone is implemented automatically by IMPLEMENT_VARIANT_OBJECT.
Since wxVariantData no longer derives from wxObject, any code that tests the
- type
- of the data using wxDynamicCast will require adjustment. You can use the macro
- wxDynamicCastVariantData with the same arguments as wxDynamicCast, to use C++
- RTTI
- type information instead of wxWidgets RTTI.
+ type of the data using wxDynamicCast will require adjustment. You can use the
+ macro wxDynamicCastVariantData with the same arguments as wxDynamicCast, to
+ use C++ RTTI type information instead of wxWidgets RTTI.
@library{wxbase}
@category{data}
class wxVariant : public wxObject
{
public:
- //@{
/**
- Construction from a ODBC timestamp value. Represented internally by a
- wxDateTime value.
+ Default constructor.
*/
wxVariant();
+
+ /**
+ Constructs a variant directly with a wxVariantData
+ object. wxVariant will take ownership of the wxVariantData
+ and will not increase its reference count.
+ */
+ wxVariant(wxVariantData* data, const wxString& name = "");
+
+ /**
+ Constructs a variant from another variant by increasing the
+ reference count.
+ */
wxVariant(const wxVariant& variant);
+
+ /**
+ Constructs a variant from a wide string literal.
+ */
wxVariant(const wxChar* value, const wxString& name = "");
+
+ /**
+ Constructs a variant from a string.
+ */
wxVariant(const wxString& value, const wxString& name = "");
+
+ /**
+ Constructs a variant from a wide char.
+ */
wxVariant(wxChar value, const wxString& name = "");
+
+ /**
+ Constructs a variant from a long.
+ */
wxVariant(long value, const wxString& name = "");
+
+ /**
+ Constructs a variant from a bool.
+ */
wxVariant(bool value, const wxString& name = "");
+
+ /**
+ Constructs a variant from a double.
+ */
wxVariant(double value, const wxString& name = "");
+
+ /**
+ Constructs a variant from a list of variants
+ */
wxVariant(const wxVariantList& value,
const wxString& name = "");
+
+ /**
+ Constructs a variant from a void pointer.
+ */
wxVariant(void* value, const wxString& name = "");
+
+ /**
+ Constructs a variant from a pointer to an wxObject
+ derived class.
+ */
wxVariant(wxObject* value, const wxString& name = "");
- wxVariant(wxVariantData* data, const wxString& name = "");
+
+ /**
+ Constructs a variant from a wxDateTime.
+ */
wxVariant(wxDateTime& val, const wxString& name = "");
+
+ /**
+ Constructs a variant from a wxArrayString.
+ */
wxVariant(wxArrayString& val, const wxString& name = "");
- wxVariant(DATE_STRUCT* val, const wxString& name = "");
- wxVariant(TIME_STRUCT* val, const wxString& name = "");
- wxVariant(TIMESTAMP_STRUCT* val, const wxString& name = "");
- //@}
/**
Destructor.
*/
~wxVariant();
+ /**
+ @name List functionality
+ */
+ //@{
+ /**
+ Returns the value at @a idx (zero-based).
+ */
+ wxVariant operator [](size_t idx);
+ /**
+ Returns a reference to the value at @a idx (zero-based). This can be used
+ to change the value at this index.
+ */
+ const wxVariant& operator [](size_t idx);
/**
Appends a value to the list.
*/
void Append(const wxVariant& value);
-
+ /**
+ Deletes the contents of the list.
+ */
+ void ClearList();
+ /**
+ Deletes the zero-based @a item from the list.
+ */
+ bool Delete(size_t item);
+ /**
+ Returns the number of elements in the list.
+ */
+ size_t GetCount() const;
+ /**
+ Returns a reference to the wxVariantList class used by
+ wxVariant if this wxVariant is currently a list of variants.
+ */
+ wxVariantList& GetList() const;
/**
Makes the variant null by deleting the internal data and
set the name to @e wxEmptyString.
*/
void Clear();
-
/**
- Deletes the contents of the list.
+ Inserts a value at the front of the list.
*/
- void ClearList();
+ void Insert(const wxVariant& value);
+ /**
+ Makes an empty list. This differs from a null variant which has no data;
+ a null list is of type list, but the number of elements in the list is zero.
+ */
+ void NullList();
+ //@}
//@{
/**
const bool Convert(wxDateTime* value) const;
//@}
- /**
- Deletes the zero-based @a item from the list.
- */
- bool Delete(size_t item);
-
/**
Returns the string array value.
*/
*/
wxChar GetChar() const;
- /**
- Returns the number of elements in the list.
- */
- size_t GetCount() const;
-
/**
Returns a pointer to the internal variant data. To take ownership
of this data, you must call its wxVariantData::IncRef
*/
double GetDouble() const;
- /**
- Returns a reference to the wxVariantList class used by
- wxVariant if this wxVariant is currently a list of variants.
- */
- wxVariantList GetList() const;
-
/**
Returns the integer value.
*/
*/
wxObject* GetWxObjectPtr() const;
- /**
- Inserts a value at the front of the list.
- */
- void Insert(const wxVariant& value);
-
/**
Returns @true if there is no data associated with this variant, @false if there
is data.
*/
bool Member(const wxVariant& value) const;
- /**
- Makes an empty list. This differs from a null variant which has no data; a null
- list
- is of type list, but the number of elements in the list is zero.
- */
- void NullList();
-
/**
Sets the internal variant data, deleting the existing data if there is any.
*/
const bool operator ==(const wxDateTime& value) const;
//@}
- //@{
- /**
- Returns a reference to the value at @a idx (zero-based). This can be used
- to change the value at this index.
- */
- wxVariant operator [](size_t idx);
- const wxVariant& operator [](size_t idx);
- //@}
-
//@{
/**
Operator for implicit conversion to a long, using GetLong().
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