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Actually, I´ve always programmed xla add-ins for Excel and have just started to be interested in c++. Most of the codes I program are finantial functions to be used in Excel and I wish to build a dll file with all of them, but Visualc++ IDE is still too complex for me. I wonder if someone could help me with a code sample. For instance, let´s suppose I define the simple following function:
double sums (double a, double b)
{
return a+b;
}
What steps should I follow to build the dll file?
How can I call the function from the VBA editor?
Can the spreadsheet user call it as Excel worksheet functions?
God bless you if you can help me. Thanks.
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I'm looking for ideas on how to make a CWnd-derived window behave like a CDialog, especially in what concerns the DoModal behaviour. By this I mean encapsulating the whole window life cycle inside a function call. By calling the function or class method, the window would be created and destroyed at the user command. Only then the function / method would return.
Any ideas?
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Hello,
I've designed my report by Crystal Report 8.5
And right now i'm using Crystal Report ActiveX in my project.
I'm looking for a way to show the report of a special record number, directly.
For example, i wanna show the report of Record number 4.
NEED FOR SPEED 
Is there any way ?
Regards,
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I have created a dll with a function that creates an array of structures. The calling application supplies a pointer that gets filled in by the dll call. The application then loops through the number of structures created by the dll call, and makes use of the info.
My plan was to have the application do the clean up as it looped through the returned data. When I call delete within the loop, I get a crash/assertion that I think is telling me that the objects were created on a different heap.
Is there a better way to do this? I don't want to have the applications call a enumerateXXX() type call where they have to identify a callback. I thought it would be best to just have them call something like this:
<br />
applications code:<br />
<br />
int nNum = 0;<br />
DSTRUCT *pds = NULL;<br />
mydllGetData(&nNum,&pData);<br />
for (int x = 0;x < nNum;x++){<br />
delete pds;
pds++;<br />
}<br />
<br />
dll code:<br />
mydllGetData(int *pNum,DSTRUCT &pds)<br />
{<br />
DSTRUCT *pNewDS = new DSTRUCT[15];<br />
*pds = pNewDS;<br />
*pNum = 15;<br />
<br />
}<br />
Thanks for any ideas you may have.
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you can override new and delete for those objects and have them allocate from the global heap (via GlobalAlloc). that lets you keep your code looking like it does above. otherwise, as you've discovered, you can't share pointers allocated inside a DLL with the client application.
-c
When history comes, it always takes you by surprise.
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Thank you for the reply.
This will be a stupid question:
I am familiar with how to override new/delete for classes, but not for struct's. Can this be done, or do I have to change my struct to a class?
Thanks again.
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if these are C-style structs (typedef struct {....}), you could just allocate all the structs as one chunk of memory: GlobalAlloc(GPTR, sizeof(DSTRUCT) * numStructs). it's just like you would do with malloc.
if they are C++ structs (which are pretty much just classes with everything public by default), you can just override new/delete for that class (or struct).
-c
When history comes, it always takes you by surprise.
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There are two problems here:
1. You're trying to delete the elements of the array individually. You allocate the array as one block of 15 elements and then you try to delete each element one at a time. That's not going to work. You must free the entire array in one shot:
delete [] pData;
2. Allocating on the DLL and then freeing on the app is generally a bad idea. If the memory is not allocated/freed the same way across both modules, it will cause a crash. So it's best to stick with the policy of making the one who creates the memory be the one who frees it.
Add a mydllFreeData member:
void mydllFreeData(DSTRUCT* pds)
{
delete [] pds;
}
Regards,
Alvaro
The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing. -- Albert Einstein
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Hi,
I have a function like this:
CStringArray CSearch::SearchNode(CString csDesiPin)
{
CStringArray a;
a.Add("test");
return a;
}
But when I try to compile there is an error:
error C2558: class 'CStringArray' : no copy constructor available
Why is that, what is wrong?
Thanks in advance!
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Since you are not passing a pointer, a copy of the CStringArray is needed. If you derive a class from CStringArray, you can create a copy constructor to do this. An easier method would be to pass a pointer to a CStringArray, and not create a second CStringArray within the function.
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I find it's better to pass in an object like this by reference as a parameter instead of returning a pointer. I usually return an error code instead.
As a rule, the standard collection of containers is a far better choice than the tinker toys that ship with MFC.
Christian
No offense, but I don't really want to encourage the creation of another VB developer.
- Larry Antram 22 Oct 2002
C# will attract all comers, where VB is for IT Journalists and managers - Michael
P Butler 05-12-2002
It'd probably be fairly easy to make a bot that'd post random stupid VB questions, and nobody would probably ever notice - benjymous - 21-Jan-2003
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Christian Graus wrote:
As a rule, the standard collection of containers is a far better choice than the tinker toys that ship with MFC.
You never miss a chance, do you? 
Regards,
Alvaro
The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing. -- Albert Einstein
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Alvaro Mendez wrote:
You never miss a chance, do you?
Not if I can help it, no. I've been too quiet on this forum for some time, and *someone* needs to make a stand for righteousness....
Christian
NO MATTER HOW MUCH BIG IS THE WORD SIZE ,THE DATA MUCT BE TRANSPORTED INTO THE CPU. - Vinod Sharma
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Preach it brother! Halleluya!
By the way, I went to a Christian church for the first time a couple of weeks ago and saw the preacher "healing" a bunch of cancer-ridden people. As he was chanting over each one of them, I noticed that several of them were fainting and falling backwards, just like on TV! 
What is your explanation for this behavior?
Also, I was only there for about 30 minutes -- got there late -- and I swear I must have counted about 30 Halleluyas coming from the preacher. Overall, it was an interesting experience.
Regards,
Alvaro
The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing. -- Albert Einstein
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Alvaro Mendez wrote:
saw the preacher "healing" a bunch of cancer-ridden people.
Hmmm... According to the Bible, anyone can pray to God and expect to be healed. I know several people healed of cancer, including one who was prayed for when not a Christian and was converted as a result of being healed by God.
Alvaro Mendez wrote:
As he was chanting over each one of them, I noticed that several of them were fainting and falling backwards, just like on TV!
Urg.
Alvaro Mendez wrote:
What is your explanation for this behavior?
Groupthink ? Basically people fall over because they know it's expected of them/encouraged. The Bible has nothing to say about people falling over, it's part of the circus many 'modern' churches engage in. In fact, they call it being 'slain in the Spirit', the closest the Bible comes to referring to this is when God *KILLED* people in the Old Testament who opposed Him. The 'slain of the Spirit' in the Bible were dead, dead, dead.
Christian
NO MATTER HOW MUCH BIG IS THE WORD SIZE ,THE DATA MUCT BE TRANSPORTED INTO THE CPU. - Vinod Sharma
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I spawn a modeless CDialog derived object from my MDI view class. When the user closes this CDailog with the system menu, I want to get rid of it totally.....
I did a new to create it in the View. If I put a delete this in the destructor of the cdialog is that enough? Also I created this object locally. Is there a problem with that and doing the delete? (if indeed the delete is legal..?)
Appreciate your help,
ns
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Some points:
1. Putting "delete this" in the destructor will not work. If the destructor is being called it's because the object is already being destroyed. So if you try to destroy it again... 
2. The proper way to get rid of modeless dialog boxes is with DestroyWindow. Call that inside your OnCancel or OnOK functions. Alternately, you can do a "delete this" instead, which will call DestroyWindow. However, "delete this" will blow up if the dialog box is not created with new every time, so be careful.
3. If the dialog is modeless, the user will be able to create more than one of it. If that's not OK with you, how do you prevent it?
Regards,
Alvaro
The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing. -- Albert Einstein
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urgh.....only one Cdialog to be created....I havent thought of it yet...maybe set some sort of flag?
I dont have an onOK or onCancel.....I just want the dlg dismissed with the system menu. So thats why I thought if I did delete this in OnClose() it might work? I didnt state this yet so what do you think about this idea?
you said" it will blow up..." why ?
Appreciate your help,
ns
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Here's what I would do:
1. Use this code to create the dialog box:
static CMyDlg s_dlg;
if (!::IsWindow(s_dlg.m_hWnd))
s_dlg.Create(CMyDlg::IDD, this);
s_dlg.ShowWindow(SW_SHOWNORMAL);
2. Inside your OnClose, call DestroyWindow();
This ensures your dialog is created only once and that it's properly destroyed.
ns wrote:
you said" it will blow up..." why ?
Sorry, typo. I modified my post. I meant that it will blow up if you call delete this and the dialog is not created with new. It's because it will try to free memory from the heap which wasn't allocated on the heap to begin with.
Regards,
Alvaro
The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing. -- Albert Einstein
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Many thanks!
Quick question:
I've got three (actually decided at run time) buttons on my project and each will spawn a CDialog. If I use the same variable s_dlg is it okay? (No static right? )THe only things i will do with these CDlgs is a. close them, or b.resize them. So in the OnClose, with your strategy, will the code know which window to destroy? SInce now s_dlg is only pointing to the last CDlg created....
Appreciate your help,
ns
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Well, if it's 3 separate dialog boxes, I recommend you create 3 separate methods, each with its own static object:
void CMyView::OnButton1()
{
static CMyDlg s_dlg;
s_dlg.Create(this);
}
void CMyView::OnButton2()
{
static CMyDlg s_dlg;
s_dlg.Create(this);
}
void CMyView::OnButton3()
{
static CMyDlg s_dlg;
s_dlg.Create(this);
}
Then you can add this method to your dialog class:
void CMyDlg::Create(CWnd* pParentWnd)
{
if (!::IsWindow(m_hWnd))
CDialog::Create(IDD, pParentWnd);
ShowWindow(SW_SHOWNORMAL);
}
Regards,
Alvaro
The world is a dangerous place, not because of those who do evil, but because of those who look on and do nothing. -- Albert Einstein
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Great article! Also need to know ....this CDialog is merely informational. So I dont refresh it (may resize it), so is it better to use a local variable or a member variable? I can easily push the pointers onto a vector, so thats not a problem....I just dont knoew if its necessary> Can I use the info in the article in the event that I create a local variable each time the button is pressed to spawn a new dlg?
Appreciate your help,
ns
what I have are a set of cdlgs which in turn send messagse to the view when their button is pressed, wehich spawns the other CDlg. SO yes I can have many CDlgs - thats okay, but only one for each original CDlg which sent the message (the one with buttons)
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