wxAny Class Reference

#include </home/zeitlin/src/wx/github/interface/wx/any.h>

---

Detailed Description

The wxAny class represents a container for any type.

Its value can be changed at run time, possibly to a different type of value.

wxAny is a backwards-incompatible (but convertible) successor class for wxVariant, essentially doing the same thing in a more modern, template- based manner and with transparent support for any user data type.

Some pseudo-code'ish example of use with arbitrary user data:

    void SomeFunction()
    {
        MyClass myObject;
        wxAny any = myObject;

        // Do something
        // ...

        // Let's do a sanity check to make sure that any still holds
        // data of correct type.
        if ( any.CheckType<MyClass>() )
        {
            // Thank goodness, still a correct type.
            MyClass myObject2 = any.As<MyClass>();
        }
        else
        {
            // Something has gone horribly wrong!
            wxFAIL();
        }
    }

When compared to wxVariant, there are various internal implementation differences as well. For instance, wxAny only allocates separate data object in heap for large objects (i.e. ones with size more than WX_ANY_VALUE_BUFFER_SIZE, which at the time of writing is 16 bytes).

Library:  wxBase

Category:  Data Structures

参照:

wxAnyValueType, wxVariant, Caveats When Not Using C++ RTTI

Public Member Functions
	wxAny ()
	Default constructor.
template<typename T >
	wxAny (const T &value)
	Constructs wxAny from data.
	wxAny (const wxAny &any)
	Constructs wxAny from another wxAny.
	wxAny (const wxVariant &variant)
	Constructs wxAny, converting value from wxVariant.
	~wxAny ()
	Destructor.
template<typename T >
T	As () const
	This template function converts wxAny into given type.
template<typename T >
bool	CheckType () const
	Use this template function for checking if this wxAny holds a specific C++ data type.
template<typename T >
bool	GetAs (T *value) const
	Template function that retrieves and converts the value of this wxAny to the type that T* value is.
bool	GetAs (wxVariant *value) const
	Specialization of GetAs() that allows conversion of wxAny into wxVariant.
const wxAnyValueType *	GetType () const
	Returns the value type as wxAnyValueType instance.
bool	HasSameType (const wxAny &other) const
	Returns true if this and another wxAny have the same value type.
bool	IsNull () const
	Tests if wxAny is null (that is, whether there is no data).
void	MakeNull ()
	Makes wxAny null (that is, clears it).
Assignment operators
template<typename T >
wxAny &	operator= (const T &value)
wxAny &	operator= (const wxAny &any)
wxAny &	operator= (const wxVariant &variant)
Equality operators
bool	operator== (signed char value) const
bool	operator== (signed short value) const
bool	operator== (signed int value) const
bool	operator== (signed long value) const
bool	operator== (wxLongLong_t value) const
bool	operator== (unsigned char value) const
bool	operator== (unsigned short value) const
bool	operator== (unsigned int value) const
bool	operator== (unsigned long value) const
bool	operator== (wxULongLong_t value) const
bool	operator== (float value) const
bool	operator== (double value) const
bool	operator== (bool value) const
bool	operator== (const char *value) const
bool	operator== (const wchar_t *value) const
bool	operator== (const wxString &value) const
Inequality operators
bool	operator!= (signed char value) const
bool	operator!= (signed short value) const
bool	operator!= (signed int value) const
bool	operator!= (signed long value) const
bool	operator!= (wxLongLong_t value) const
bool	operator!= (unsigned char value) const
bool	operator!= (unsigned short value) const
bool	operator!= (unsigned int value) const
bool	operator!= (unsigned long value) const
bool	operator!= (wxULongLong_t value) const
bool	operator!= (float value) const
bool	operator!= (double value) const
bool	operator!= (bool value) const
bool	operator!= (const char *value) const
bool	operator!= (const wchar_t *value) const
bool	operator!= (const wxString &value) const

List of all members.

---

Constructor & Destructor Documentation

wxAny::wxAny

(

)

Default constructor.

It seeds the object with a null value.

template<typename T >

wxAny::wxAny

(

const T &

value

)

Constructs wxAny from data.

wxAny::wxAny

(

const wxAny &

any

)

Constructs wxAny from another wxAny.

wxAny::wxAny

(

const wxVariant &

variant

)

Constructs wxAny, converting value from wxVariant.

注意:

Because of this conversion, it is not usually possible to have wxAny that actually holds a wxVariant. If wxVariant cannot be converted to a specific data type, wxAny will then hold and manage reference to wxVariantData* similar to how wxVariant does.

wxAny::~wxAny

(

)

Destructor.

---

Member Function Documentation

template<typename T >

T wxAny::As

(

)

const

This template function converts wxAny into given type.

In most cases no type conversion is performed, so if the type is incorrect an assertion failure will occur.

注意:

For conveniency, conversion is done when T is wxString. This is useful when a string literal (which are treated as const char* and const wchar_t*) has been assigned to wxAny.

This template function may not work properly with Visual C++ 6. For full compiler compatibility, please use wxANY_AS(any, T) macro instead.

template<typename T >

bool wxAny::CheckType

(

)

const

Use this template function for checking if this wxAny holds a specific C++ data type.

注意:

This template function may not work properly with Visual C++ 6. For full compiler compatibility, please use wxANY_CHECK_TYPE(any, T) macro instead.

参照:

wxAnyValueType::CheckType()

bool wxAny::GetAs

(

wxVariant *

value

)

const

Specialization of GetAs() that allows conversion of wxAny into wxVariant.

Returns:

Returns true if conversion was successful. Conversion usually only fails if variant used custom wxVariantData that did not implement the wxAny to wxVariant conversion functions.

template<typename T >

bool wxAny::GetAs

(

T *

value

)

const

Template function that retrieves and converts the value of this wxAny to the type that T* value is.

Returns:

Returns true if conversion was successful.

const wxAnyValueType* wxAny::GetType

(

)

const

Returns the value type as wxAnyValueType instance.

注意:

You cannot reliably test whether two wxAnys are of same value type by simply comparing return values of wxAny::GetType(). Instead, use wxAny::HasSameType().

参照:

HasSameType()

bool wxAny::HasSameType

(

const wxAny &

other

)

const

Returns true if this and another wxAny have the same value type.

bool wxAny::IsNull

(

)

const

Tests if wxAny is null (that is, whether there is no data).

void wxAny::MakeNull

(

)

Makes wxAny null (that is, clears it).

bool wxAny::operator!=

(

const wxString &

value

)

const

bool wxAny::operator!=

(

wxLongLong_t

value

)

const

bool wxAny::operator!=

(

unsigned char

value

)

const

bool wxAny::operator!=

(

unsigned short

value

)

const

bool wxAny::operator!=

(

unsigned int

value

)

const

bool wxAny::operator!=

(

signed long

value

)

const

bool wxAny::operator!=

(

unsigned long

value

)

const

bool wxAny::operator!=

(

wxULongLong_t

value

)

const

bool wxAny::operator!=

(

float

value

)

const

bool wxAny::operator!=

(

bool

value

)

const

bool wxAny::operator!=

(

const char *

value

)

const

bool wxAny::operator!=

(

const wchar_t *

value

)

const

bool wxAny::operator!=

(

double

value

)

const

bool wxAny::operator!=

(

signed char

value

)

const

bool wxAny::operator!=

(

signed short

value

)

const

bool wxAny::operator!=

(

signed int

value

)

const

template<typename T >

wxAny& wxAny::operator=

(

const T &

value

)

wxAny& wxAny::operator=

(

const wxAny &

any

)

wxAny& wxAny::operator=

(

const wxVariant &

variant

)

bool wxAny::operator==

(

unsigned short

value

)

const

bool wxAny::operator==

(

unsigned char

value

)

const

bool wxAny::operator==

(

double

value

)

const

bool wxAny::operator==

(

bool

value

)

const

bool wxAny::operator==

(

signed short

value

)

const

bool wxAny::operator==

(

signed char

value

)

const

bool wxAny::operator==

(

const wxString &

value

)

const

bool wxAny::operator==

(

const wchar_t *

value

)

const

bool wxAny::operator==

(

signed long

value

)

const

bool wxAny::operator==

(

unsigned int

value

)

const

bool wxAny::operator==

(

float

value

)

const

bool wxAny::operator==

(

wxULongLong_t

value

)

const

bool wxAny::operator==

(

wxLongLong_t

value

)

const

bool wxAny::operator==

(

const char *

value

)

const

bool wxAny::operator==

(

signed int

value

)

const

bool wxAny::operator==

(

unsigned long

value

)

const