|
If I pass a quoted string variable to the LPVOID argument of a method it accepts it but if I pass a CString to the LPVOID augument I get a compiler error, cannot convert from 'CString' to 'LPVOID'. Can anyone help me with getting the data from a CString into an LPVOID data type?
Kyle
|
|
|
|
|
Convert first to LPCTSTR then maybe LPSTR then to LPVOID.
|
|
|
|
|
Tom Archer shared this answer with me so I wanted to share it with others. Thanks Tom!
It's easy. Just call the CString::GetBuffer function. Here's an example where I have a function that takes an LPVOID and another function that calls it twice (once passing a hard coded literal and then with a CString). Note that I'm using VC7. You might need to call GetBuffer(0) in VC6.
void CallTest()
{
Test("abc");
CString str = "def";
Test(str.GetBuffer()); // This is what you need to do in your case.
}
void Test(LPVOID lp)
{
AfxMessageBox((const char*)lp);
}
That should set you up.
Cheers,
Tom
It did! Thanks again Tom.
|
|
|
|
|
You're welcome, mate. Like I say in the Acknowledgements section of my C# book, being able to share code and help each other on sites like this is one very big reason that programming remains fun after all these years.
Cheers,
Tom Archer
Author, Inside C#
A total abstainer is one who abstains from everything but abstention, and especially from inactivity in the affairs of others.
|
|
|
|
|
Hey Tom
He said you helped him, but I cant see where 
It puzzles me no end!
Nish
Check out last week's Code Project posting stats presentation from :-
http://www.busterboy.org/codeproject/
Feel free to make your comments.
|
|
|
|
|
On another thread he had asked about how to use the registry and I sent him a simple class (CRegistry) I had written for my MFC book (Visual C++.NET Bible). He then asked how to call one of the member functions (WriteString) that takes an LPVOID since the value he wants to pass is in a CString. He must have posted the question here at the same time he emailed me. When I responded, he then updated this thread.
Can you tell that I've been writing books for too long?  I can't say good morning to someone in less than 50 words any more! Damn editors and their request for more detail!! 
Cheers,
Tom Archer
Author, Inside C#
A total abstainer is one who abstains from everything but abstention, and especially from inactivity in the affairs of others.
|
|
|
|
|
Tom Archer wrote:
Visual C++.NET Bible
So, Tom , in this book, you are writing specifically about MFC 7 ???
Cheers,
Joao Vaz
Frustrated TCL programmer,good c++ programmer wannabe
|
|
|
|
|
Yes, the VC++.NET book is 95% MFC. I have about 5 chapters at the end on ME, but that's not the focus of the book. Those chapters are more like "if you're interested in this here's some stuff to get you started".
Personally, I don't think many people are going to to use ME so I wanted to keep the book focus on MFC. I really hate that publishers are not making this clear in their book titles. I wish the ME books would state in the title (Managed Extensions). As it is now, the readers have no idea just by looking at the title.
Cheers,
Tom Archer
Author, Inside C#
A total abstainer is one who abstains from everything but abstention, and especially from inactivity in the affairs of others.
|
|
|
|
|
To be totally honest with you ,IMHO I think that you should need badly the money(the pool isn't in a great shape), personally I don't like the publisher of your forthcoming book , and I hate their Bible Series .
Apart from that what will be intended level of audience of the book? Beginner/Intermediate?
Now concerning your Inside C#, 2nd, I don't have any doubt that it rocks, although, for money constraints, I will only buy your book on the next 3 months (very optimistic way, by the end of this month) , my company insists in delaying my bonus payment (2 salaries) that I and my fellow colleagues have right
Cheers,
Joao Vaz
Frustrated TCL programmer,good c++ programmer wannabe
|
|
|
|
|
Joao Vaz wrote:
To be totally honest with you ,IMHO I think that you should need badly the money(the pool isn't in a great shape), personally I don't like the publisher of your forthcoming book , and I hate their Bible Series
That's cool. However, I think if you look at my MFC book, you'll definitely like it. It's really a labour of love at this point. You see, this was the first book I was ever a part of. The book was never strong overall and so I always wanted to redo it by myself. I've almost completely rewritten it and it is much stronger now. There are a couple of chapters still are still held over from the other author, but 95% of this 1300 page book is solid.
Joao Vaz wrote:
Apart from that what will be intended level of audience of the book? Beginner/Intermediate?
The book can be used by beginners as I do have some beginner level chapters to start the text. However, you can easily skip over those to get to the meaty stuff. For example, there's some really cool stuff on controls, dialogs, COM/ATL (9 chapters), database access, DLLs, COM+, etc. I hope I don't sound immodest here, but my book answers about 50% of the questions I've seen on this board and I would definitely compare it to any other MFC book (including Prosise's) in terms of completeness. (By the way, note that I know Jeff personally and mean that with a great deal of respect for his work.)
Joao Vaz wrote:
I will only buy your book on the next 3 months
No problem. I'll need sales then too
Cheers,
Tom Archer
Author, Inside C#
A total abstainer is one who abstains from everything but abstention, and especially from inactivity in the affairs of others.
|
|
|
|
|
Tom Archer wrote:
It's really a labour of love at this point
It isn't very difficult for you, you are a complet programmer freak 
Tom Archer wrote:
but 95% of this 1300 page book is solid.
 , a trully effort without a doubt and synonym of endless coding and writing nights ...
Tom Archer wrote:
but my book answers about 50% of the questions I've seen on this board
It's better that it succeds , with 1300 pags ! Serioulsly ,if it answers 50% then is a certainly a good book .
Tom Archer wrote:
I would definitely compare it to any other MFC book (including Prosise's) in terms of completeness
Now that's enough !!!! (conspiracy theory) You certainly want your name immortalized as great programming author , first with Inside C# , then with VC++ .Net Bible, then , who knows MC++ ? Shame on you , you bad boy ! You are respected more than enough by your peers, MFC and C# programmers , and you want more !!!!! I caught you, you want to say I'm the king of the
world !!! I'll defend the CPians with all my ... scratching ... but I'm corruptible ... if you offer me your 2nd of Inside C# with a signed autograph, then I'll forget and let you do what your evil mind planned .
Tom Archer wrote:
No problem. I'll need sales then too
Every penny is welcome
Cheers,
Joao Vaz
Frustrated TCL programmer,good c++ programmer wannabe
|
|
|
|
|
Joao Vaz wrote:
It isn't very difficult for you, you are a complet programmer freak
Very true It's so cool for our jobs to also be our hobbies.
Joao Vaz wrote:
a trully effort without a doubt and synonym of endless coding and writing nights
You got the endless night bit, right. I am so glad to be done. It's been fun, but it's time to move on to another project.
Joao Vaz wrote:
Now that's enough !!!! (conspiracy theory) You certainly want your name immortalized as great programming author , first with Inside C# , then with VC++ .Net Bible, then , who knows MC++ ? ...you want to say I'm the king of the
world !!!
I guy's gotta have a plan
Joao Vaz wrote:
I'll defend the CPians with all my ... scratching ... but I'm corruptible ... if you offer me your 2nd of Inside C# with a signed autograph, then I'll forget and let you do what your evil mind planned
Cheers,
Tom Archer
Author, Inside C#
A total abstainer is one who abstains from everything but abstention, and especially from inactivity in the affairs of others.
|
|
|
|
|
|
Er....remember when I recommended that you not leave yourself so open
Cheers,
Tom Archer
Author, Inside C#
A total abstainer is one who abstains from everything but abstention, and especially from inactivity in the affairs of others.
|
|
|
|
|
kyledunn wrote:
Tom Archer shared this answer with me so
When and where?
Nish
Check out last week's Code Project posting stats presentation from :-
http://www.busterboy.org/codeproject/
Feel free to make your comments.
|
|
|
|
|
Answered in your other query for same
Cheers,
Tom Archer
Author, Inside C#
A total abstainer is one who abstains from everything but abstention, and especially from inactivity in the affairs of others.
|
|
|
|
|
Tom Archer wrote:
Answered in your other query for same
Thanks. I saw it.
In the confuision I forgot my original reason.
You told him to use GetBuffer, but I think you didnt tell him about RelkeaseBuffer
Nish
Check out last week's Code Project posting stats presentation from :-
http://www.busterboy.org/codeproject/
Feel free to make your comments.
|
|
|
|
|
Call ReleaseBuffer is not necessary in this context.
Cheers,
Tom Archer
Author, Inside C#
A total abstainer is one who abstains from everything but abstention, and especially from inactivity in the affairs of others.
|
|
|
|
|
I emailed Tom directly. He responded shortly before I posted his help here.
Kyle
|
|
|
|
|
Convert first to LPCTSTR then maybe LPSTR then to LPVOID. These are all pointers, CString isn't so you need to convert to a pointer first. The internal data structure of a cstring object is an LPCTSTR pointer; you acess it directly by calling GetBuffer(int nmax),but you also have to call ReleaseBuffer() after .
|
|
|
|
|
When i construct a query containng the query which conatins either the single quotes or double quotes then the query crashes . Can anyone suggest the solution
Samir
|
|
|
|
|
Samir Sood wrote:
When i construct a query containng the query which conatins either the single quotes or double quotes then the query crashes . Can anyone suggest the solution
For each quote you have in a string, add an extra quote.
Thus if you want to insert a string such as "John's Bakers" into a table, insert it as "John''s Bakers" and all will be well
Nish
Check out last week's Code Project posting stats presentation from :-
http://www.busterboy.org/codeproject/
Feel free to make your comments.
|
|
|
|
|
But what if string contains the double quotes as part of it
|
|
|
|
|
As Nish said, you need to double up on the quotes. For example, Access chokes on quotes in a string value because it uses quotes as the string delimiter. Therefore, here's a function I wrote a few years ago to do what you need. It only handles single quotes, but obviously you can easily modify it for your needs.
CString FormatValidAccessString(CString const & sStringToBeFormatted)
{
CString sFormattedString;
int iStringLength = sStringToBeFormatted.GetLength();
char cChar;
for (int i = 0; i < iStringLength; i++)
{
cChar = sStringToBeFormatted.GetAt(i);
sFormattedString += cChar;
if ('\'' == cChar)
{
sFormattedString += cChar;
}
}
return sFormattedString;
}
Cheers,
Tom Archer
Author, Inside C#
A total abstainer is one who abstains from everything but abstention, and especially from inactivity in the affairs of others.
|
|
|
|
|
Or to keep it really simple...
CString cMyString = "string possibly containing chars that need to be escaped...";
cMyString.Replace("'", "''");
If I remember correctly you can even get the string quotation character from ADO (the connection object probably)
so that your code is a little bit more provider independent. It's usually " for "real" databases
|
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
