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Would I catch the CUserException in my BN_CLICKED message handler and carry out my additional functions before throwing the exception on?
Thanks in advance,
Graham
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Data transfer/validation happens when UpdateData is called. MFC will call UpdateData for you in its OK handler. You may also call this method 'manually' in response to some event. Are you calling UpdateData yourself?
Tomasz Sowinski -- http://www.shooltz.com
Never argue with an idiot, he'll bring you to his level and beat you with experience.
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I'm calling UpdateData() in my BN_CLICKED message handler to send the data from the controls to the variables. At the end of the function, after I have manipulated the variables, I call UpdateData(FALSE) to send the data back to the controls.
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Your first call to UpdateData should be in try..catch block. Please note that MFC throws 'CUserException *'.
Tomasz Sowinski -- http://www.shooltz.com
Never argue with an idiot, he'll bring you to his level and beat you with experience.
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Sorry - you need to provide try..catch in DoDataExchange. Otherwise CWnd::UpdateData will catch and process the exception.
Tomasz Sowinski -- http://www.shooltz.com
Never argue with an idiot, he'll bring you to his level and beat you with experience.
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So within DoDataExchange I have to provide the code:
try
{
// code
}
catch (CUserException* e)
{
// carry out resetting of variables
}
Do I also have to throw the exception?
Thanks,
Graham
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gm_coll wrote:
Do I also have to throw the exception?
Yes. Just use 'throw' without arguments, which transfers control to upper-level catch handler.
Tomasz Sowinski -- http://www.shooltz.com
Never argue with an idiot, he'll bring you to his level and beat you with experience.
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Sorry, I'm still confused.
If I use a try..catch block in DoDataExchange what do I put in the try block, because what I am trying to do is transfer the data from the controls to the variables and this should already have happened. Will this not have already generated an exception when the data containing non-numeric characters is attempted to map to my double?
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gm_coll wrote:
Will this not have already generated an exception when the data containing non-numeric characters is attempted to map to my double?
Yes, the exception was already generated and user has seen the MFC's message box. But you wanted to do something extra (at least this is what you originally posted). The catch block in DoDataExchange is your chance - you're getting control before DoDataExchange returns to CWnd::UpdateData.
Tomasz Sowinski -- http://www.shooltz.com
Never argue with an idiot, he'll bring you to his level and beat you with experience.
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Hi,
I have a simple smart pointer implementation. Now, I want the pointer to allow type casting. For example, a derived class should be able to cast back to the base class etc. Any ideas on how to do this?
Here is the implementation so far:
template <class t="">
class SmartPtr
{
public:
/**
Default constructor.
*/
SmartPtr(): _p (0) {}
/**
Pass new directly as the argument
*/
SmartPtr (T* p): _p (p) {}
/**
Copy constructor
*/
SmartPtr(SmartPtr& source) :_p(source.Acquire())
{}
/**
Assignment operator: transfers ownership
*/
SmartPtr& operator= (SmartPtr& pSource)
{
if (_p != pSource._p)
{
delete _p;
_p = pSource.Acquire();
}
}
/**
Delete the pointer, when going out of scope.
The pointer does not get deleted if the owner has changed
*/
~XPtr () { delete _p; }
/**
Null out the pointer. So if the owner has changed and
this object goes out of scope, it does not delete the pointer.
*/
T* Acquire ()
{
T * pTmp = _p;
_p = 0;
return pTmp;
}
/**
for pointer like syntax
*/
T * operator->() { return _p; }
/**
Get the raw pointer
*/
T const & GetAccess () const { return *_p; }
private:
/**
The raw pointer
*/
T * _p;
};
Thanks,
Pankaj
Without struggle, there is no progress
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Add 'operator T* () { return _p; }'
Tomasz Sowinski -- http://www.shooltz.com
Never argue with an idiot, he'll bring you to his level and beat you with experience.
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Thanks! That worked! However, how is it that we do not have to supply any return type? Does C++ automatically determine the return type according to the casting operator. Also, I did not know that a class function could be without a return type. However, it works! So obviously I need to learn a lot! Any input on this will be greatly appreciated!
Pankaj
Without struggle, there is no progress
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Without wishing to sound nasty or dificult or stupid...is this smart pointer implementation giving you anything more than auto_ptr in the Standard C++ Library - and if not, why not just use that?
Stuart Dootson
'Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p'
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I know I can use auto_ptr. I am not really using it in any project. It just feels good to know that you can implement this behavior sometime. Also, gives me a better understanding of the language and everything. Basically, just for educational purposes. That is all 
Pankaj
Without struggle, there is no progress
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Hey, that's cool - I've often done things to educate myself - experience IS the best way to learn. Just wanted to make sure you weren't implementing it because you didn't know about the already written alternatives!!
Stuart Dootson
'Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p'
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Hi!
I recently ported several my projects from VC6 to VC7. I have noticed large memory leaks. After some debugging, I have found out that ExitInstance is not called any more. This is due to fact, that window is destroyed far more earlier (I think) than before. Application exits (quits ,immediately) in CFrameWnd::OnClose() during DestroyWindow() - last line in this method.
What is the reason?
I cannot find any document which describes this issue.
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hi!!
anyone can help me?
i want to know that thru consloe program can we pass the values to windows program & can invoke the windows application to display the output.
plz help me
thanks!!
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Yes it depends on the task u want to do, but to launch an application Nishat S has a good article on code project
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thanks for replying!
but from where can i get this article.
plz tell me.
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thanks for replying!
but from where can i get this article.
plz tell me.
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http://www.codeproject.com/system/newbiespawn.asp
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How I can use "BindDefaultProperty" of an editbox
to bind a field of a disconnected recordset.
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Hi all,
How can i change the font of Text Box (Edit Box) ?.
With regards
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Did you try with SetFont?
Tomasz Sowinski -- http://www.shooltz.com
Never argue with an idiot, he'll bring you to his level and beat you with experience.
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Hi all,
I have plced a Bitmap in my control in a static frame using the Load Image Function.Now the bitmap is seen as a compressed or expanded one depending on the bitmap selected to load in that frame. How can i make the bitmap to fit in my frame with the full size in such a manner that the visible part of the image is seen on the static frame and the remaining portions are seen when a scroll bar at bottom or side is moved?. In short how can i show a bitmap in a static frame with scrolling using load Image Function?.
With regards
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