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Hi all,
I have two functions of a class and i want to call these two functions inside many functions which
are derived from other classes.I don;t want to create an object of the class to which the function belongs everywhere.Is there a way out how i can accomplish this.
If making a function static will help:
Regards
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create the class as a member varible of the class to which you call the functions
ClassA has m_classB
ClassB
has the functions your after.
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Yes you can use static functions for that. You can have like a utility class that you can put helper functions in there. Example usage will be like the following code:
//========================
class A{
public:
static void myprint(){
printf("static hello ! \n");
}
};
class B{
public:
void func(){
A::myprint(); // Here you call the static myprint without having to create an object of class A
}
};
int main()
{
B *poB = new B();
poB->func();
A::myprint() // Again, you can call myprint with no object creation
}
//========================
The output of this will be :
static hello!
static hello!
Hope that helps 
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However you have to take care of static functions and use these only if you are sure that they fit to your design.
An alternative way to do this is to just derive the classes that needs your functions from the class they belong to. i.e
class A{
public:
void funcA();
void funcB();
};
class B: public A { // inherits class A
// this class now can use the funcA and funcB as its own
};
Its basic OO C++
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nice didn't know that or atleast i forgot about it
more likely i missed it in a lecture due to me 
knew that static keeps the varibles and function on the heep (am i correct?)
didnt realise it affected how it could be called?
is that good programming standard or not?
thanks sam
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mmm not exactly. If I remember correctly they are allocated in their own memory space. Cannot remember the name though.. have to look it up.
Regarding whether or not is a good programming standard or not...well...it depends on how to use them.
They should be avoided if another way is possible and good OO techniques should be used instead.
Sometimes they are usefull though and their use might be required.
Of course I wouldn't use static functions all over the place because static functions have their limitations and so they should be used with care.
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Thanks i was needing this answer.
Regards,
Mayank
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Maynka wrote: I don;t want to create an object of the class to which the function belongs everywhere.
You don't need to create objects everywhere, you can accomplish the task with a single instance of the class (the better way to do this is explained by the singleton design pattern).
Maynka wrote: If making a function static will help:
Probably this is the most natural solution, because it seems that you don't need to access instance members in your functions (and, indeed, you cannot access such members in static functions).
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
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Hi, I am new to Visual C++ programming and this is my first time posting on this forum. I am hoping someone can help me out.
I recently used and modified a class derived from CStatic so that I could have a CStatic box that gives me the ability to color particular words in the box. In order to do this I had to override the OnPaint since it had to change the text color it was painting for those particular words. I was fighting with this for a while to get scrolling to work and I thought I had everything the way I needed it.
My problem is that I realized that with the way I have it set up the user is not allowed to do text selection on the painted text. With my App the user must have the ability to select the text off of the CStatic window so that it can be pasted in another location. How do I make the text selectable?
As I said I am new to Visual C++ programming so don't necessarily assume I have tried anything you may think would be obvious.
Thanks,
Derrick
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the user is not allowed to do text selection on the painted text
I could hardly believe this is the case. The problem might be in redrawing the selected text. IOW, the text selected is not shown as being selected. If so, this is a problem from your drawing algorithm. What are you doing in OnPaint? Are you calling the base class's OnPaint?
--
=====
Arman
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I am not calling the base classes OnPaint. My OnPaint is as follows:
void CStaticColor::OnPaint()
{
CPaintDC dc(this); // device context for painting
// TODO: Add your message handler code here
CString staticText = m_delimitedString;
if (staticText != "") {
//Set Font
CFont font;
CFont* pOldFont;
if (font.CreateFont(14, 0, 0, 0, FW_NORMAL, FALSE, FALSE, FALSE, ANSI_CHARSET,
OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS, PROOF_QUALITY,
DEFAULT_PITCH & FF_DONTCARE, "Courier")) {
pOldFont = dc.SelectObject(&font);
}
CRect rect;
GetClientRect(&rect);
//Data Sizing
int newLinePos = 0;
int oldLinePos = 0;
staticTextHeight = 0;
staticTextWidth = 0;
while(newLinePos != -1) {
staticTextHeight += 13;
oldLinePos = newLinePos;
newLinePos = staticText.Find("\r\n",newLinePos + 1);
if ( ( ( newLinePos - oldLinePos ) * 8) > staticTextWidth ) {
staticTextWidth = ( ( newLinePos - oldLinePos ) * 8 );
}
}
//Vertical Scroll Code
if (staticTextHeight > rect.Height()) {
this->EnableScrollBar(SB_VERT, ESB_ENABLE_BOTH);
this->ShowScrollBar(SB_VERT);
SCROLLINFO si = {0};
si.cbSize = sizeof(si); // size of this structure
si.fMask = SIF_RANGE | SIF_PAGE; // parameters to set
si.nMin = 0; // minimum scrolling position
si.nMax = (staticTextHeight); // maximum scrolling position
si.nPage = rect.Height(); // the page size of the scroll box
//si.nPos = 0; // initial position of the scroll box
//si.nTrackPos = 0; // immediate position of a scroll box that the user is dragging
this->SetScrollInfo(SB_VERT, &si, TRUE);
}
else {
ShowScrollBar( SB_VERT, FALSE ); // Hide it
SetScrollPos( SB_VERT, 0 );
}
//Horizontal Scroll Code
if (staticTextWidth > rect.Width()) {
this->EnableScrollBar(SB_HORZ, ESB_ENABLE_BOTH);
this->ShowScrollBar(SB_HORZ);
SCROLLINFO si = {0};
si.cbSize = sizeof(si); // size of this structure
si.fMask = SIF_RANGE | SIF_PAGE; // parameters to set
si.nMin = 0; // minimum scrolling position
si.nMax = (staticTextWidth); // maximum scrolling position
si.nPage = rect.Width(); // the page size of the scroll box
//si.nPos = 0; // initial position of the scroll box
//si.nTrackPos = 0; // immediate position of a scroll box that the user is dragging
this->SetScrollInfo(SB_HORZ, &si, TRUE);
}
else {
ShowScrollBar( SB_HORZ, FALSE ); // Hide it
SetScrollPos( SB_HORZ, 0 );
}
dc.SetBkMode(TRANSPARENT);
CRect outRect(0,0,rect.Width(),rect.Height());
// Create a rect above our target rect that will not allow drawing to.
RECT excluderect;
excluderect.top = outRect.top - GetScrollPos( SB_VERT);
excluderect.bottom = outRect.top;
excluderect.left = outRect.left;
excluderect.right = outRect.right;
dc.ExcludeClipRect(&excluderect);
// Create a rect to the left of our target rect that will not allow drawing to.
RECT excluderect2;
excluderect2.top = outRect.top;
excluderect2.bottom = outRect.bottom;
excluderect2.left = outRect.left - GetScrollPos( SB_HORZ);
excluderect2.right = outRect.left;
dc.ExcludeClipRect(&excluderect2);
//Create a rect to the right of our target rect that will not allow drawing to.
RECT excluderect3;
excluderect3.top = outRect.top;
excluderect3.bottom = outRect.bottom;
excluderect3.left = outRect.right;
excluderect3.right = max(outRect.right, ( outRect.right + (staticTextWidth - outRect.Width()) - GetScrollPos( SB_HORZ) ) );
dc.ExcludeClipRect(&excluderect3);
// Draw the text accounting for any scrolling of the vertical scroll bar.
outRect.top -= GetScrollPos( SB_VERT );
leftRect = outRect.left -= GetScrollPos( SB_HORZ );
outRect.right = max((staticTextWidth +2 - GetScrollPos( SB_HORZ) ), outRect.right);
DrawText(&dc, staticText, &outRect, DT_LEFT | DT_WORDBREAK);
}
// Do not call CStatic::OnPaint() for painting messages
}
Let me know if you need to see my DrawText() or if you have any other questions. I appreciate any help on this.
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This seems awfully complicated for just changing a control's text color. Why not handle the WM_CTLCOLORSTATIC message instead?
"A good athlete is the result of a good and worthy opponent." - David Crow
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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I beleive that that message will change the color for all the text in a particular static window. With my program I just want to make certain words within the cstatic a different color. This derived class changes the color by looking for a particular character flag within the text and changing the color until the next flag. I do not want to change the text of the entire cstatic box or this would be a much simpler problem.
Thanks for the comment though. As I said before I can copy the entire string from within the cstatic using shortcut keys but I cannot select portions of the text with the mouse to do a copy. Any ideas on this?
-Derrick
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Derrick Becker wrote: With my program I just want to make certain words within the cstatic a different color.
A richedit control would do this much, much easier.
"A good athlete is the result of a good and worthy opponent." - David Crow
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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As I said I am new to Visual C++ programming. How might I go about this with a richedit control? Can I insert some character sequence into the string to tell the richedit to change colors? Or would I have to derive a class from richedit to do this? And if I did derive the class are you telling me that I would not need to override the OnPaint function of the richedit since it would have functions built in to change parts of the string?
Thanks,
Derrick
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Derrick Becker wrote: ...are you telling me that I would not need to override the OnPaint function of the richedit since it would have functions built in to change parts of the string?
Correct.
"A good athlete is the result of a good and worthy opponent." - David Crow
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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Well I think I will look into using richedit then instead of cstatic. As I said I am new to visual c++ programming and I was informed I should use and overridden class of cstatic to get colors. The rich edit may be a better option though.
If possible to just make the cstatic selectable though I would like to find that information since I have it all set up with the cstatic derived class with everything working but the text selection.
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Derrick Becker wrote: The rich edit may be a better option though.
Definitely.
Derrick Becker wrote: If possible to just make the cstatic selectable though I would like to find that information since I have it all set up with the cstatic derived class with everything working but the text selection.
Even if you did somehow manage to get it working, you'd still be stuck swimming upstream (i.e, going against the grain) from this point forward.
"A good athlete is the result of a good and worthy opponent." - David Crow
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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Alright you've convinced me to go ahead and try to make the rich edit's work. btw I think the two different conversations at the same time is somewhat funny.
Thanks
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I just did some more testing and I noticed that if you have the cstatic window open and do a Control+A and Control+C to copy all text it will copy and I can paste the entire window to another App but I still cannot do specific text selections. Any help would be greatly appreciated.
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Ok. You cannot do a selection in a static control. Instead, you can prepare a CEdit derived class and make it readonly. This will look like a static control but with a capability of selection. (You might also consider CRichEditCtrl class which has a functions to format its content).
--
=====
Arman
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I tried to derive my class from CEdit instead and it seemed to have the same exact output and issues. You said earlier "the text selected is not shown as being selected", could this be the problem? The old version of this App used a CStatic control that was read only and allowed text selection. I would like this same ability only with color, so it should not be a limitation in the CStatic since the old one with a regular CStatic could do text selection.
Thanks for all your help, let me know what else you think please.
-Derrick
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Derrick Becker wrote: The old version of this App used a CStatic control that was read only and allowed text selection.
Are you 100% sure about this? A read-only edit control with no border/edge will look exacly like a static control. The only difference being that you can select text from the edit control whereas you cannot from the static control.
"A good athlete is the result of a good and worthy opponent." - David Crow
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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Yes in the header file they were declared as CStatic and text could be highlighted. I think maybe the person that created the first one may have used an Edit box through the resource editor and then manually changed it to a CStatic if that makes a difference because if you go to the properties of the dialog through the resource editor it says "Edit Properties" at the top.
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The way to find out definitely is to use Spy++ on the control itself. Just run the application, open the dialog that contains the control in question, run Spy++ and drag the finder tool over the control. Note the type of control and its styles.
"A good athlete is the result of a good and worthy opponent." - David Crow
"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne
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