C / C++ / MFC

2-Jul-04 19:14

I need to convert CString value to const char *. I do the same in following way. I also tried with LPCTSTR, still i get same error.
CString filename;
FILE *fptr;

m_fileName.GetWindowText(filename);
int nLen = filename.GetLength();
LPTSTR lpszString = filename.GetBuffer (nLen );
fptr = fopen( lpszString, "r" );

But i get error as
fopen' : cannot convert parameter 1 from 'unsigned short *' to 'const char *'
Types pointed to are unrelated; conversion requires reinterpret_cast, C-style cast or function-style cast

i need ur help to sole this issue.

Ken Mazaika2-Jul-04 19:19

Ken Mazaika

2-Jul-04 19:19

I'm not sure if this will work, but have you tried simply setting the LPTSTR equal to the CString? I think CString has an LPTSTR operator if memory serves...

-Kmaz

sugumar2-Jul-04 19:27

2-Jul-04 19:27

CString is not able to be assigned with LPTSTR,

LPTSTR lpszString = filename;

gives error

error C2440: 'initializing' : cannot convert from 'class CString' to 'unsigned short *' No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called

PJ Arends2-Jul-04 19:38

PJ Arends

2-Jul-04 19:38

CString has an LPCTSTR operator, so you can pass a CString object to any function that requires a LPCTSTR

fptr = fopen(m_fileName, _T("r"))

CString::GetBuffer() returns a LPTSTR, not a LPCTSTR.

LPTSTR is a char*
LPCTSTR is a const char*

"You're obviously a superstar." - Christian Graus about me - 12 Feb '03

"Obviously ??? You're definitely a superstar!!!" mYkel - 21 Jun '04

Within you lies the power for good - Use it!

sugumar2-Jul-04 19:48

2-Jul-04 19:48

m_fileName is CEdit type. Also i hv to collect string value from CstringArray like this..
CStringArray* aXMLfiles;
CString filename;
int mlen = aXMLfiles->GetSize();
// write all the XML files
for(j=0;j<mlen;j++)
{
filename="aXMLfiles-">GetAt(j);
LPTCSTR lpszString = filename;
fptr = fopen( lpszString, "r" );
////do something////
}
still i get error.

Johan Rosengren2-Jul-04 20:56

2-Jul-04 20:56

You can take away the extra assignment, this is enough:

fopen( filename, "r" );

or this:

fopen( ( LPCTSTR ) filename, "r" );

If not, your problem lies elswhere, and you might want to post some more code.

sugumar2-Jul-04 22:00

2-Jul-04 22:00

still problem continues.I put the code for ur ref.
CStringArray* aXMLfiles;
int mlen,j;
CString filename;
FILE *fptr;
aXMLfiles = GetFileNames("*.XML"); /// This function retrives me all XML files..
mlen = aXMLfiles->GetSize();
for(j=0;j<mlen;j++)
{
="" filename="aXMLfiles-">GetAt(j);
fptr = fopen( ( LPCTSTR ) filename, "r" );

if (fptr != NULL){
// do something }

}

fopen' : cannot convert parameter 1 from 'class CString' to 'const char *'
No user-defined-conversion operator available that can perform this conversion, or the operator cannot be called.

Johan Rosengren2-Jul-04 22:09

2-Jul-04 22:09

As CString has a user-defined operator LPCTSTR, the "or the operator cannot be called"-part of the error message seems to be the interesting part. What is the error number (CXXXX) you get?

markkuk2-Jul-04 22:42

markkuk

2-Jul-04 22:42

Are you using Unicode? The complaint about "unsigned short*" looks like you are trying to feed wide characters to a function that understands only 8-bit chars.

cmk3-Jul-04 10:05

cmk

3-Jul-04 10:05

This is why i stopped using CString.
It's an all or nothing proposition.

If you compile for UNICODE then it wraps an array of wchar_t (unsigned short).
If you compile for ANSI then it wraps an array of char.

You can't cast between the two, you must convert.
Use wcstombs to go from a wchar_t to char.
Use mbstowcs to go from a char to wchar_t.

[EDIT]
Actually what you should do if using CString is go the whole way and use all the _t funtion versions. e.g. _tfopen() will work with a CString regardless of it being UNICODE or ANSI. Most functions that take a char* have a _t*() version. Check the MSDN doc's.
[/EDIT]

...cmk

Save the whales - collect the whole set

Dialogbox

Ken Mazaika2-Jul-04 18:57

Ken Mazaika

2-Jul-04 18:57

I want to make a dialog popup like a toolbox, but be a resizable dialog with controls i want on it. I've seen it in some other applications and I would like to add it to one of mine. Any links/ideas/suggestions would be appreciated.

-Kmaz

Re: Dialogbox

Johan Rosengren2-Jul-04 20:59

2-Jul-04 20:59

You want a resizable, modeless dialog. It's not different from a normal dialog, but you select resizable border from the styles in the resource editor, and call Create instead of DoModal. Add a member of the dialog class to the parent class, call Create as soon as possible (after the parent window is created, this depends on the kind of window), and then call ShowWindow to show/hide the toolbox.

Re: Dialogbox

Ken Mazaika3-Jul-04 4:41

Ken Mazaika

3-Jul-04 4:41

I can't believe i didnt think of that...I'm an idiot Big Grin | :-D

Re: Dialogbox

Johan Rosengren3-Jul-04 5:43