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Sorry,i have a fause discription.i want know that:i.e,i have drawn a rectangle ,when Mouse in it ,there is an text displaying its message.
云鹤 I'm a beginer of MFC. what i want to do is changing an apple with you.Of course, the important is learning from all of you.
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yunhe wrote:
i have drawn a rectangle ,when Mouse in it ,there is an text displaying its message
You mean tooltip? What do you need to know that is not covered here[^]?
Who is 'General Failure'? And why is he reading my harddisk?!?
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I have 2 Dialogs. The first calls the second,
in which i create CEdit fields dynamically. To store
them i put them in a CStringToOb (filterMap) in the first dialog:
CEdit* edit = new CEdit();
edit->Create(....);
ptr_to_main->filterMap[i] = (CObject*) edit;
When i go back i want to read the input made
to the CEdit Fields. The Only Posibility i found to do so is :
CEdit* pvalue;
ptr_to_main->filterMap.Lookup( i, ( CObject*& )pvalue);
pvalue->GetLine(1,value);
The Point is I dont get anything when calling GetLine.
When i do the same with Strings it works. What am i doing wrong ?
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You both dialogs are valid till the above code executes? Check whether the control contains data when you access edit control again...Can you explain in more detail?
VikramS
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Trying to give some hints :
Looking at the MSDN in the CEdit description of GetLine :
int GetLine( int nIndex, LPTSTR lpszBuffer )
nIndex : Specifies the line number to retrieve from a multiple-line edit control. Line numbers are zero-based; a value of 0 specifies the first line. This parameter is ignored by a single-line edit control
So do you have a single or multiline edit control ?
And if its a multiline edit .... ever tried to use GetLine( 0, ...) instead of GetLine( 1,...) ?
If you only have single lines ... try to use :
CString csValue = "";
CEdit* pvalue;
ptr_to_main->filterMap.Lookup( i, ( CObject*& )pvalue);
pvalue->GetWindowText( csValue );
I hope it helps ... a bit.
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thanks !
I foundout myself that GetWindowText is the proper
method to do so. It confused me cause with some fields this method reads out the caption instead of the value...
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 I’d like to build communication program between Personal Computer and Microchip PIC device. I use WIN32 API functions. But I have troubles with Receiving Part on the PC Side. I need some help to understand the action of functions and collaborations between them ! I am feeling like a blind one, when I am writing the code.
What I need and what are my questions ?
I need more information about the whole Receiving Process, about the synchronization between the Parts of the Process, and about the roles of the WIN32 API functions (in the context of the Data Receiving.
Now, some specific questions.
- Organization of stable waiting cycle – it must be endless and I must have control over it
To exit whet I want, or when some period expired, or … - what functions I need and what are the proposal parameters ?
- What is the difference between: communication event and object ?
- Is the communication event an object ?
- About WaitCommEvent:
“If hFile was not opened with FILE_FLAG_OVERLAPPED, WaitCommEvent does not return until one of the specified events or an error occurs” – I need to define some waiting time, … some ideas ?
- Can I use WaitForSingleObject ?
It allow me to define some waiting time ?
- About ReadFile functions: If I don’t know the number of receiving symbols … ?
To finish – I need something like receiving part of Microsoft Hyper Terminal ?
Any kind of information, devoted to these topics will be useful for me .
Thank You !
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Check this
http://www.codeproject.com/system/simpleserialcomm.asp
http://www.thecodeproject.com/system/cserialport.asp
And what are you trying to do whith the PIC?
Is it a 16F877 or 16F84?
Papa
while (TRUE)
Papa.WillLove ( Bebe ) ;
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basic things of reference and pointer but can anybody explain me how they operate differently
thax
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reference is nothing but a constant pointer.
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Really?
try compilling these
const int* p = NULL;
and
int& l = NULL;
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ok correction ...for most purposes a reference can be looked at as a constant pointer.
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i think reference is address of the object..
unlike pointer, u cannot delete reference
pointer is links to memory but reference sit on the top of the object..
reference never be the pointer ,
reference just another name of the object.
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reference is internally implemented as a constant pointer with some conditions.
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some of them have already been mentioned in this thread.
One more is
* reference has to be initialized when defined, but pointer need not be
e.g.
const int* p;
int& l; //error here
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References may be implemented as pointers (though not constant ones as someone has said), but this is unimportant from the user's point of view.
I guess you already know what a pointer is, so let's focus on references. You can think of a reference to an object as an alias to that object, i.e. an alternate name for the object. So:
int a=0;
int& b=a;
b=1;
cout<<a; In this example a and b refer to the very same object.
There is a common use of references as convenient arguments to function. Consider:
void f(int i)
{
i=1;
}
int a=0;
f(a);
cout<<a; f is not doing what you intended because you are passing the value of a, not the variable itself (in terms of implementation, you're passing an int constructed from a.) What f needs is the "name" of the object:
void f(int& i)
{
i=1;
}
int a=0;
f(a);
cout<<a; Get the idea? Of course you could have gotten the same effect using pointers, in this case at least it is a matter of convenience and style which solution you use.
References are somewhat hard to grasp, keep on reading good C++ stuff and the concept will progressively build in your mind.
Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
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I would say it is not a matter of style and convenience. In most circumstances only pass pointers into functions if you need the possibility that the object is not valid, i.e. null pointer.
It is a matter of the compiler catching errors or having them show up at runtime.
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It is a matter of the compiler catching errors or having them show up at runtime.
I don't think substituting references for pointers in function declarations catches any error at runtime. For instance, consider a program like this
void foo(int *i);
...
f(something);
f(&something); If I change the definition of foo to allegedly make it more robust, the whole program has to be changed as
void foo(int& i);
...
f(*something);
f(something); Any program compiling with the first definition of foo will compile just the same with the second definition (after modifying the invocations to foo.) So, you won't catch more errors at compile time.
References can help prevent problems at compile time, but not when used as function arguments --rather, when replacing pointer variables declarations with reference variables declarations, as in
int * p;
int& p=...
Anyway replacing pointers with references is not always feasible, if the concept of null object is valid, or if the pointer must be rebound (references cannot.)
Joaquín M López Muñoz
Telefónica, Investigación y Desarrollo
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Well what I meant was
<br />
void FOO(int* p){*p+=1;}<br />
<br />
int* i = NULL;<br />
FOO(i)<br />
If you use references then this sort of problem just can not occur.
So it is not that an error will be caught at compile time, there can be no error if you use references.
Anyway replacing pointers with references is not always feasible, if the concept of null object is valid, or if the pointer must be rebound (references cannot.)
I agree and that is what I said.
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Can anybody tell me structure of make file how it is used and link with different environment
thanx
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Hi everybody;P
I want to transfer a byte to parallel port, but i can't. Somebody help me do it.
Thanks,
hung
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