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How to pass CMyDoc object or pointer to function of another class called from CMyDoc::Func()
Hello
I want to pass CMyDoc reference or pointer to another class function. How to do this?
Class CMydoc
{
public:
int i;
};
CMyDoc::Func()
{
}
This is class Try and is in different file - Try.cpp:
Class Try
{
FuncTry(CMydoc *pDoc);
};
Try::FuncTry(CMydoc *pDoc)
{
char cc[10];
AfxMessageBox(_itoa(cc,pDoc->i,10));
}
CMyDoc::Func()
{
//code
m_TryObj.Try(this);
//code
}
Snakekaa
There could be several methods depending of the PLACE WHERE YOU CALL THE Try::FuncTry() method.
1. USING A GLOBAL VARIABLE
- You define a global variable in the MyDoc.cpp file like this:
CMyDoc *pMyDoc;
- In the constructor of the CMyDoc class (file MyDoc.cpp), initialize this global variabile: pMyDoc = this;
- In the file where you call the method Try::FuncTry() , (this could be anyplace in the code, let's assume the file is
called xxx.cpp), declare the pMyDoc variable as external like this: extern CMyDoc *pMyDoc.
- In the file xxx.cpp where u are using the method Try::FuncTry() simply use the global variable pMyDoc:
FuncTry(pMyDoc);
WARNING: U SHOULD BE AWARE HOWEVER THAT IF U DESTROY THE DOCUMENT THE ADRESS POINTED BY THE pMyDoc WON'T BE VALID, SO PAY
ATTENTION !!!
2. I assume that u are using a SDI application. The following code will work just fine for a SDI app. , but if you understand it u will be able to make it work for MDI app too.
I also assumed here that u are calling the TryFunc() from a function called OnTest() in class CMainFrame(). The code will also work without problems even if u are calling the TryFunc() in any other place.
That's all. Tell me if it helped, or rate me, or hate me :)Code:// get a reference to the CWinApp object from which CMyApp is derived
CWinApp *pMainApp = AfxGetApp();
ASSERT(pMainApp);
// we need this pointer in order to call the GetFirstDocTemplatePosition() function
POSITION pos = pMainApp->GetFirstDocTemplatePosition();
CDocTemplate *pDocTemplate = pMainApp->GetNextDocTemplate(pos);
ASSERT(pDocTemplate);
// at this point we have a reference to the document template, and because we are
// a SDI application we do not continue the iteration
pos = pDocTemplate->GetFirstDocPosition();
CMyDoc *pMyDoc = (CMyDoc *)pDocTemplate->GetNextDoc(pos);
ASSERT(pMyDoc);
// instantiate our Try object and call the FuncTry() method
Try objTry;
objTry.FuncTry(pMyDoc);
Query:
WHy i am getting error when i will put extern CContourAnalyserDoc *pMyDoc; in xxx.h instead of xxx.cpp
-------------------------
Hello I am facing problem in passing CMyDoc pointer to another class function.
It is basically in function defination. I am givig file wise details and where i am facing problem.
File: CMyData.h
#include "CMyDoc.h"
File: CMyData.cpp
void CMyData::Calc(CMyDoc *pDoc)
{
}
Note: CMyData is polymorphic base class of three other classes.
So based on pointer available in CMyDoc particular polymorphic subclass's Func function is called.
File CMyView.cpp
CMyView::Func()
{
CMyData dat;
CMyDoc *pDoc = this->GetDocument();
dat.Calc(*pDoc);
}
PROB. 1:I am getting syntax error : identifier 'CMyDoc' if i am removing CMyDoc header from my CMyData.h file
PROB 2.: If i am keeping the "#include "CMyDoc.h" in CMyData.h file then i get following error
undeclared base class CMyData
Main Aim: main aim is to pass CMyDoc *p pointer to the class for calculation.
Any suggestions, help , idea,
T.I.A.
my suggestion is NOT to use global variables. it's C++ afterall :)
see the attached for a more detailed view.
Hello
Thanks for your reply but still my query in second post remains un-answered
i.e. how to pass CMyDoc's pointer to a function of another class in CMyView.cpp
2.0 What should be the function signature or defination?
I tried with following but resulted in error i.e. CMyDoc unresolved identifier even i had included header file of CMyDoc in CMyData
void Func(CMyDoc *pDoc);
Plz. reply soon
TIA
Waiting for any kind of help related to this.
:confused:
Well....the first question would be what you need the pointer for. And what kind of is the other class. It might not be necessary to pass around the document pointer at all depending on your answers to the former questions. Take a look at the following FAQ.
If you still need to pass the document pointer, you simply use the following signature
'CMyDocument' needs to be the name of your document class you want to pass (or if you are using RTTI you can use the base class 'CDocument' and cast appropriate).Code:void Func(CMyDocument *pPointer)
{
}
Thanks Andreas
i will try to implement the same and will look after this. If any problem then i will put a query.
Thanks again
HELLO ANDREAS
I tried to do this fro a class Cxx.cpp to get pointer of CDoc.
CDocument *doc =AfxGetMainWnd()->GetActiveView()->GetDocument();
but error came
error C2039: 'GetActiveView' : is not a member of 'CWnd'
from MSDN: folowing is the function of CFrameWnd so do i have to use CFrameWnd instead of CWnd ? hOW TO DO THIS?
Well...you have to cast explicitly here...Quote:
Originally posted by d0153030
HELLO ANDREAS
I tried to do this fro a class Cxx.cpp to get pointer of CDoc.
CDocument *doc =AfxGetMainWnd()->GetActiveView()->GetDocument();
but error came
error C2039: 'GetActiveView' : is not a member of 'CWnd'
from MSDN: folowing is the function of CFrameWnd so do i have to use CFrameWnd instead of CWnd ? hOW TO DO THIS?
I have used the base classes 'CView' and 'CMainFrame' in the above sample, they might differ from yours, so you would need to adjust them accordingly. Potentially, you might have to cast the returned document pointer as well...Code:CDocument *doc = static_cast<CView*>(static_cast<CMainFrame*>(AfxGetMainWnd())->GetActiveWindow())->GetDocument();