wxstring.tex

很牛的GUI源码wxWidgets-2.8.0.zip 可在多种平台下运行.

bit numbers is not supported by the underlying C run-time library. Compilers
with C99 support and Microsoft Visual C++ version 7 and higher do support this.

\wxheading{See also}

\helpref{wxString::ToLong}{wxstringtolong},\\
\helpref{wxString::ToULongLong}{wxstringtoulonglong}


\membersection{wxString::ToULong}\label{wxstringtoulong}

\constfunc{bool}{ToULong}{\param{unsigned long}{ *val}, \param{int }{base = $10$}}

Attempts to convert the string to an unsigned integer in base {\it base}.
Returns \true on success in which case the number is stored in the
location pointed to by {\it val} or \false if the string does not
represent a valid number in the given base. Please notice that this function
behaves in the same way as the standard \texttt{strtoul()} and so it simply
converts negative numbers to unsigned representation instead of rejecting them
(e.g. $-1$ is returned as \texttt{ULONG\_MAX}).

See \helpref{wxString::ToLong}{wxstringtolong} for the more detailed
description of the {\it base} parameter.

\wxheading{See also}

\helpref{wxString::ToDouble}{wxstringtodouble},\\
\helpref{wxString::ToLong}{wxstringtolong}


\membersection{wxString::ToULongLong}\label{wxstringtoulonglong}

\constfunc{bool}{ToULongLong}{\param{wxULongLong\_t}{ *val}, \param{int }{base = $10$}}

This is exactly the same as \helpref{ToULong}{wxstringtoulong} but works with 64
bit integer numbers.

Please see \helpref{ToLongLong}{wxstringtolonglong} for additional remarks.


\membersection{wxString::Trim}\label{wxstringtrim}

\func{wxString\&}{Trim}{\param{bool}{ fromRight = true}}

Removes white-space (space, tabs, form feed, newline and carriage return) from
the left or from the right end of the string (right is default).


\membersection{wxString::Truncate}\label{wxstringtruncate}

\func{wxString\&}{Truncate}{\param{size\_t}{ len}}

Truncate the string to the given length.


\membersection{wxString::UngetWriteBuf}\label{wxstringungetwritebuf}

\func{void}{UngetWriteBuf}{\void}

\func{void}{UngetWriteBuf}{\param{size\_t }{len}}

Puts the string back into a reasonable state (in which it can be used
normally), after
\rtfsp\helpref{wxString::GetWriteBuf}{wxstringgetwritebuf} was called.

The version of the function without the {\it len} parameter will calculate the
new string length itself assuming that the string is terminated by the first
{\tt NUL} character in it while the second one will use the specified length
and thus is the only version which should be used with the strings with
embedded {\tt NUL}s (it is also slightly more efficient as {\tt strlen()} 
doesn't have to be called).


\membersection{wxString::Upper}\label{wxstringupper}

\constfunc{wxString}{Upper}{\void}

Returns this string converted to upper case.


\membersection{wxString::UpperCase}\label{wxstringuppercase}

\func{void}{UpperCase}{\void}

The same as MakeUpper.

This is a wxWidgets 1.xx compatibility function; you should not use it in new code.


\membersection{wxString::wc\_str}\label{wxstringwcstr}

\constfunc{const wchar\_t*}{wc\_str}{\param{wxMBConv\&}{ conv}}

\constfunc{const wxWCharBuffer}{wc\_str}{\param{wxMBConv\&}{ conv}}

Returns wide character representation of the string.
In ANSI build, converts using \arg{conv}'s \helpref{cMB2WC}{wxmbconvcmb2wc}
method and returns wxWCharBuffer. In Unicode build, this function is same
as \helpref{c\_str}{wxstringcstr}.
The macro wxWX2WCbuf is defined as the correct return type (without const).

\wxheading{See also}

\helpref{wxMBConv}{wxmbconv},
\helpref{c\_str}{wxstringcstr}, \helpref{mb\_str}{wxstringwcstr},
\helpref{fn\_str}{wxstringfnstr}


\membersection{wxString::operator!}\label{wxstringoperatornot}

\constfunc{bool}{operator!}{\void}

Empty string is \false, so !string will only return \true if the string is empty.
This allows the tests for NULLness of a {\it const wxChar *} pointer and emptiness
of the string to look the same in the code and makes it easier to port old code
to wxString.

See also \helpref{IsEmpty()}{wxstringisempty}.


\membersection{wxString::operator $=$}\label{wxstringoperatorassign}

\func{wxString\&}{operator $=$}{\param{const wxString\&}{ str}}

\func{wxString\&}{operator $=$}{\param{const wxChar*}{ psz}}

\func{wxString\&}{operator $=$}{\param{wxChar}{ c}}

Assignment: the effect of each operation is the same as for the corresponding
constructor (see \helpref{wxString constructors}{wxstringconstruct}).


\membersection{wxString::operator $+$}\label{wxstringoperatorplus}

Concatenation: all these operators return a new string equal to the
concatenation of the operands.

\func{wxString}{operator $+$}{\param{const wxString\&}{ x}, \param{const wxString\&}{ y}}

\func{wxString}{operator $+$}{\param{const wxString\&}{ x}, \param{const wxChar*}{ y}}

\func{wxString}{operator $+$}{\param{const wxString\&}{ x}, \param{wxChar}{ y}}

\func{wxString}{operator $+$}{\param{const wxChar*}{ x}, \param{const wxString\&}{ y}}


\membersection{wxString::operator $+=$}\label{wxstringplusequal}

\func{void}{operator $+=$}{\param{const wxString\&}{ str}}

\func{void}{operator $+=$}{\param{const wxChar*}{ psz}}

\func{void}{operator $+=$}{\param{wxChar}{ c}}

Concatenation in place: the argument is appended to the string.


\membersection{wxString::operator []}\label{wxstringoperatorbracket}

\func{wxChar\&}{operator []}{\param{size\_t}{ i}}

\constfunc{wxChar}{operator []}{\param{size\_t}{ i}}

\func{wxChar\&}{operator []}{\param{int}{ i}}

\constfunc{wxChar}{operator []}{\param{int}{ i}}

Element extraction.


\membersection{wxString::operator ()}\label{wxstringoperatorparenth}

\func{wxString}{operator ()}{\param{size\_t}{ start}, \param{size\_t}{ len}}

Same as Mid (substring extraction).


\membersection{wxString::operator \cinsert}\label{wxstringoperatorout}

\func{wxString\&}{operator \cinsert}{\param{const wxString\&}{ str}}

\func{wxString\&}{operator \cinsert}{\param{const wxChar*}{ psz}}

\func{wxString\&}{operator \cinsert}{\param{wxChar }{ch}}

Same as $+=$.

\func{wxString\&}{operator \cinsert}{\param{int}{ i}}

\func{wxString\&}{operator \cinsert}{\param{float}{ f}}

\func{wxString\&}{operator \cinsert}{\param{double}{ d}}

These functions work as C++ stream insertion operators: they insert the given
value into the string. Precision or format cannot be set using them, you can use 
\helpref{Printf}{wxstringprintf} for this.


\membersection{wxString::operator \cextract}\label{wxstringoperatorin}

\func{friend istream\&}{operator \cextract}{\param{istream\&}{ is}, \param{wxString\&}{ str}}

Extraction from a stream.


\membersection{wxString::operator const wxChar*}\label{wxstringoperatorconstcharpt}

\constfunc{}{operator const wxChar*}{\void}

Implicit conversion to a C string.


\membersection{Comparison operators}\label{wxstringcomparison}

\func{bool}{operator $==$}{\param{const wxString\&}{ x}, \param{const wxString\&}{ y}}

\func{bool}{operator $==$}{\param{const wxString\&}{ x}, \param{const wxChar*}{ t}}

\func{bool}{operator $!=$}{\param{const wxString\&}{ x}, \param{const wxString\&}{ y}}

\func{bool}{operator $!=$}{\param{const wxString\&}{ x}, \param{const wxChar*}{ t}}

\func{bool}{operator $>$}{\param{const wxString\&}{ x}, \param{const wxString\&}{ y}}

\func{bool}{operator $>$}{\param{const wxString\&}{ x}, \param{const wxChar*}{ t}}

\func{bool}{operator $>=$}{\param{const wxString\&}{ x}, \param{const wxString\&}{ y}}

\func{bool}{operator $>=$}{\param{const wxString\&}{ x}, \param{const wxChar*}{ t}}

\func{bool}{operator $<$}{\param{const wxString\&}{ x}, \param{const wxString\&}{ y}}

\func{bool}{operator $<$}{\param{const wxString\&}{ x}, \param{const wxChar*}{ t}}

\func{bool}{operator $<=$}{\param{const wxString\&}{ x}, \param{const wxString\&}{ y}}

\func{bool}{operator $<=$}{\param{const wxString\&}{ x}, \param{const wxChar*}{ t}}

\wxheading{Remarks}

These comparisons are case-sensitive.


\section{\class{wxStringBuffer}}\label{wxstringbuffer}

This tiny class allows to conveniently access the \helpref{wxString}{wxstring} 
internal buffer as a writable pointer without any risk of forgetting to restore
the string to the usable state later.

For example, assuming you have a low-level OS function called 
{\tt GetMeaningOfLifeAsString(char *)} returning the value in the provided
buffer (which must be writable, of course) you might call it like this:

\begin{verbatim}
    wxString theAnswer;
    GetMeaningOfLifeAsString(wxStringBuffer(theAnswer, 1024));
    if ( theAnswer != "42" )
    {
        wxLogError("Something is very wrong!");
    }
\end{verbatim}

Note that the exact usage of this depends on whether on not wxUSE\_STL is enabled.  If
wxUSE\_STL is enabled, wxStringBuffer creates a separate empty character buffer, and
if wxUSE\_STL is disabled, it uses GetWriteBuf() from wxString, keeping the same buffer
wxString uses intact.  In other words, relying on wxStringBuffer containing the old 
wxString data is probably not a good idea if you want to build your program in both
with and without wxUSE\_STL.

\wxheading{Derived from}

None

\wxheading{Include files}

<wx/string.h>

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


\membersection{wxStringBuffer::wxStringBuffer}\label{wxstringbufferctor}

\func{}{wxStringBuffer}{\param{const wxString\& }{str}, \param{size\_t }{len}}

Constructs a writable string buffer object associated with the given string
and containing enough space for at least {\it len} characters. Basically, this
is equivalent to calling \helpref{GetWriteBuf}{wxstringgetwritebuf} and
saving the result.


\membersection{wxStringBuffer::\destruct{wxStringBuffer}}\label{wxstringbufferdtor}

\func{}{\destruct{wxStringBuffer}}{\void}

Restores the string passed to the constructor to the usable state by calling 
\helpref{UngetWriteBuf}{wxstringungetwritebuf} on it.


\membersection{wxStringBuffer::operator wxChar *}\label{wxstringbufferwxchar}

\func{wxChar *}{operator wxChar *}{\void}

Returns the writable pointer to a buffer of the size at least equal to the
length specified in the constructor.



\section{\class{wxStringBufferLength}}\label{wxstringbufferlength}

This tiny class allows to conveniently access the \helpref{wxString}{wxstring} 
internal buffer as a writable pointer without any risk of forgetting to restore
the string to the usable state later, and allows the user to set the internal
length of the string.

For example, assuming you have a low-level OS function called 
{\tt int GetMeaningOfLifeAsString(char *)} copying the value in the provided
buffer (which must be writable, of course), and returning the actual length
of the string, you might call it like this:

\begin{verbatim}
    wxString theAnswer;
    wxStringBuffer theAnswerBuffer(theAnswer, 1024);
    int nLength = GetMeaningOfLifeAsString(theAnswerBuffer);
    theAnswerBuffer.SetLength(nLength);
    if ( theAnswer != "42" )
    {
        wxLogError("Something is very wrong!");
    }
\end{verbatim}

Note that the exact usage of this depends on whether on not wxUSE\_STL is enabled.  If
wxUSE\_STL is enabled, wxStringBuffer creates a separate empty character buffer, and
if wxUSE\_STL is disabled, it uses GetWriteBuf() from wxString, keeping the same buffer
wxString uses intact.  In other words, relying on wxStringBuffer containing the old 
wxString data is probably not a good idea if you want to build your program in both
with and without wxUSE\_STL.

Note that SetLength {\tt must} be called before wxStringBufferLength destructs.

\wxheading{Derived from}

None

\wxheading{Include files}

<wx/string.h>

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


\membersection{wxStringBufferLength::wxStringBufferLength}\label{wxstringbufferlengthctor}

\func{}{wxStringBufferLength}{\param{const wxString\& }{str}, \param{size\_t }{len}}

Constructs a writable string buffer object associated with the given string
and containing enough space for at least {\it len} characters. Basically, this
is equivalent to calling \helpref{GetWriteBuf}{wxstringgetwritebuf} and
saving the result.


\membersection{wxStringBufferLength::\destruct{wxStringBufferLength}}\label{wxstringbufferlengthdtor}

\func{}{\destruct{wxStringBufferLength}}{\void}

Restores the string passed to the constructor to the usable state by calling 
\helpref{UngetWriteBuf}{wxstringungetwritebuf} on it.


\membersection{wxStringBufferLength::SetLength}\label{wxstringbufferlengthsetlength}

\func{void}{SetLength}{\param{size\_t }{nLength}}

Sets the internal length of the string referred to by wxStringBufferLength to 
{\it nLength} characters.

Must be called before wxStringBufferLength destructs.


\membersection{wxStringBufferLength::operator wxChar *}\label{wxstringbufferlengthwxchar}

\func{wxChar *}{operator wxChar *}{\void}

Returns the writable pointer to a buffer of the size at least equal to the
length specified in the constructor.