Re: c control list - C / C++ / MFC Discussion Boards

Re: combobox editing

FarPointer4-Jul-06 17:59

FarPointer

4-Jul-06 17:59

BOOL LimitText( int nMaxChars );

Regards,
FarPointer
Blog:FARPOINTER

Re: combobox editing

see me4-Jul-06 18:00

see me

4-Jul-06 18:00

Use LimitText( long lLimit )

ComboBox m_Combobox;
m_Combobox.LimitText( 64 );

Smile | :)

"Dream bigger...Do bigger...Expect smaller"
aji

sending and receiving float

thathvamsi4-Jul-06 16:54

thathvamsi

4-Jul-06 16:54

hello all,
I want to serially transmit float variables/data types between the PC and the serial device (RABBIT 3000 -an 8bit microcontroller).

I am transmitting with databits as 8 for serial transmission as my microcontroller is an 8bit one.

I convert float to long and bitshift to assign it to a buffer of type char.
But if I do this, then say,
I want to transmit 3.4,then I can transmit only 3 and not the .4
as I convert form float to long before transmitting.

How can I transmit a float data variable from PC to microcontroller or the vice-versa serially.?
Confused | :confused:

Re: sending and receiving float

Nibu babu thomas4-Jul-06 17:23

Nibu babu thomas

4-Jul-06 17:23

Use...

typedef union
{
   float fFloatVar;
   UCHAR ucFloatByteArray;
}FloatConverter;
 
FloatConverter fc;
fc.fFloatVar = 23.456f;

Now just send the bytes in FloatConverter.ucFloatByteArray one by one.

Now while receiving store each byte into the byte array FloatConverter.ucFloatByteArray and then

float fFloatNumber = FloatConverter.fFloatVar;

I guess this should help you.

Thanks to toxcct...

Nibu thomas
A Developer

Programming tips[^] My site[^]

Re: sending and receiving float

thathvamsi4-Jul-06 20:34

thathvamsi

4-Jul-06 20:34

thanks very much.
It works perfectly.
thanks for ur help.

Re: sending and receiving float

Jörgen Sigvardsson4-Jul-06 23:48

Jörgen Sigvardsson

4-Jul-06 23:48

Or how about:

unsigned char* byteptr = (unsigned char*)&floatVal;
for(int i = 0; i < sizeof(float); ++i)
   Send(byteptr[i]);

You can use this technique for any struct/basic type, without having to create a "converter" union for each type.

--
For External Use Only

c control list

kamalesh824-Jul-06 16:34

kamalesh82

4-Jul-06 16:34

I need to use a ccontrol list to show data, after pressing button 'showdata'.....in a old project(DIALOG BASED).....the problem is that..... in this project i can't use class wizard.

kamalesh

Re: c control list

Sarath C4-Jul-06 19:39

Sarath C

4-Jul-06 19:39

Have you removed the wizard comments from source?

AFAIK we can use class wizard, only if we created the project by classwizard.

When pressing the Ctrl+W it will ask for the list of files. I think it appears only for the projects created through class wizard Frown | :(

SaRath.

"It is your attitude, not your aptitude, that determines your altitude - Zig Ziglar."

My Blog | Understanding State Pattern in C++

MDI with VC6.0 workspace fileview like function

zeus_master4-Jul-06 16:06

zeus_master

4-Jul-06 16:06

I set a treeview toolbar in my MDI project.
just like the VC++ 6.0 workspace toolbar,Click the item/filename of the fileview, the related file opens and become active. and insert/delete item of the tree, it will new/close the related doc/file .

1.>how to create a new file for the new item ?

2.>when DbclickTree() happens, how to active the related file?
3.>does the files can searched/sort by filename as the treeview item sort?

thanks for ur kind help!

Sorenson H.263

RedDragon2k4-Jul-06 15:45

RedDragon2k

4-Jul-06 15:45

Hey Guys,

does anybody know a good implementation of the Sorenson H.263 Codec ? I couldn't find a nice on. Well I found some links but they were dead D'Oh! | :doh:

I appreciate any help.

Thanks,
Ben

Editable comboBox

Ram Murali4-Jul-06 15:25

Ram Murali

4-Jul-06 15:25

Hi all,

I created combo box with control variable. I like to set the no of characters to be keyed in in the combobox(editable).

In brief, set the text limit to the Combobox control variable. Can anyone help me in this problem?

Thanks in Advance.

Regards,
Ram

Re: Editable comboBox

Jun Du4-Jul-06 15:52

Jun Du

4-Jul-06 15:52

Follow these steps:
1) From View menu, bring up the MFC ClassWizard
2) Add a member variable of CString type for the ComboBox
3) Set maximum characters to a number of your choice
4) Recompile the project

Best,
Jun

Re: Editable comboBox

Ram Murali4-Jul-06 16:07

Ram Murali

4-Jul-06 16:07

I already set member variable type CComboBox type to the combobox.

And now i have created one more member variable CString type as u hv specified. still i couldnt able to set the text limit to the combo box. advice on this.

Thanks.

Regards,
Ram

Re: Editable comboBox

Jun Du5-Jul-06 3:34

Jun Du

5-Jul-06 3:34

On the "Member Variable" panel, select the variable you just created. As it's a CString type, an edit box named "Maximum characters" will appear at the bottom.

Best,
Jun

Weird Class name

Jay034-Jul-06 14:53

Jay03

4-Jul-06 14:53

 class RTI_EXPORT RTIambassador {<br />
  public:<br />
#include "RTIambServices.hh"<br />
    RTIambPrivateData* privateData;<br />
  private:<br />
    RTIambPrivateRefs* privateRefs;<br />
  };<br />
<br />
  class RTI_EXPORT FederateAmbassador {<br />
  public:<br />
#include "federateAmbServices.hh"<br />
  };

WHOAA!! What is this suppose to mean
How come we have two names for this class

class RTI_EXPORT RTIambassador {<br />
<br />
.....<br />
<br />
};

Does this mean you can refer to this class by two different names

Re: Weird Class name

C^hris L^osinger4-Jul-06 15:40

C^hris L^osinger

4-Jul-06 15:40

no, it means the class is probably intended to be exported from a DLL

Cleek | Image Toolkits | Thumbnail maker

Text Length

locoone4-Jul-06 14:19

locoone

4-Jul-06 14:19

i need to know how to get the width of a string of text
.GetLength("string"); will return 6
.GetLength("String"); also returns 6
but
.GetStringWidth("string"); returns 22
.GetStringWidth("String"); returns 27 which is what i need but .GetStringWidth is part of a listctrl and i may not always use a listctrl with my class so i need a work around for it.
i hope this is clear on what i need.

Re: Text Length

C^hris L^osinger4-Jul-06 14:30

C^hris L^osinger

4-Jul-06 14:30

from the MSDN:

CListCtrl::GetStringWidth : The width, in pixels, of the string pointed to by lpsz.

CString::GetLength: A count of the bytes in the string.

bytes != pixels

Cleek | Image Toolkits | Thumbnail maker

Re: Text Length

locoone4-Jul-06 14:32

locoone

4-Jul-06 14:32

i know that i need the width in pixels just dont know how to get it.

Re: Text Length

C^hris L^osinger4-Jul-06 15:34

C^hris L^osinger

4-Jul-06 15:34

in that case, you need to :

1. create a font object that reflects the font you're going to use when you draw the text
2. create a DC
3. select your font into that DC
4. use something like DrawTextEx or CDC::GetTextExtent to measure the text

Cleek | Image Toolkits | Thumbnail maker

Syntax related question [modified]

Jay034-Jul-06 11:37

Jay03

4-Jul-06 11:37

class Derived: public string <br />
{<br />
public:<br />
  ~ Derived() { --destr;}<br />
};<br />
int main()<br />
{<br />
  string * p = new Derived;<br />
  //...use p<br />
  delete p; // undefined behavior<br />
  cout>> destr >>endl; // surprise! n is still 0<br />
}

Class Derived publicly inherits from Class String

My question is, is

String *p = new Derived;

same as

String *p;<br />
p = new Derived;

-- modified at 17:38 Tuesday 4th July, 2006

Re: Syntax related question

Jörgen Sigvardsson4-Jul-06 11:47

Jörgen Sigvardsson

4-Jul-06 11:47

Deriving from std::string is asking for trouble...

--
Based on a True Story

virtual destructors [modified]

Jay034-Jul-06 10:59

Jay03

4-Jul-06 10:59

what are virual destructors? I'm tryin to understand this file
why do we have a destructor function from a derived class which is empty

class ObjectRoot <br />
{<br />
public:<br />
<br />
virtual ~ObjectRoot<br />
<br />
};<br />
<br />
<br />
<br />
class Ball : public ObjectRoot <br />
{<br />
public :<br />
<br />
virtual ~Ball<br />
};<br />
<br />
ObjectRoot::~ObjectRoot<br />
{<br />
......<br />
......<br />
......<br />
}<br />
<br />
<br />
Ball::~Ball <br />
{<br />
//empty<br />
}

CAN ANYONE TELL ME WHAT IS GOING ON HERE PLZ Confused | :confused:

-- modified at 16:59 Tuesday 4th July, 2006

Re: virtual destructors

Joe Woodbury4-Jul-06 11:13

Joe Woodbury

4-Jul-06 11:13

The virtual destructor allows the destructor of derived classes to be called when deleting the instance through the base class.

In other words, an instance of Ball can be assigned to an ObjectRoot pointer:

ObjectRoot* pBase = (ObjectRoot*) new Ball;

and then deleted:

delete pBase;

The virtual destructor ensures that Ball's destructor will be called.

Often, destructors do nothing, but the empty virtual implementation is left just in case something later is added.

Anyone who thinks he has a better idea of what's good for people than people do is a swine.
- P.J. O'Rourke

Re: virtual destructors

Jörgen Sigvardsson4-Jul-06 12:02

Jörgen Sigvardsson

4-Jul-06 12:02

class A {
public:
   A() { }
   ~A() { }
};
 
class B : public A {
public:
   B() { }
   ~B() { }
};
 
B* b = new B();
delete b; // calls B::~B() and then A::~A() automatically
A* a = new B();
delete a; // calls A::~A() only, leaving stuff initialized by B::B() uninitialized

When a C++ compiler sees a method call, it first checks to see if the method is virtual or not. If it is not virtual, it will use the object variable's static type information, to determine what method to call. If the variable is of type B*, it will first look in B's definition, and fallback on A if no matching method could be found.

If the method is virtual, the compiler will generate code which calls the method furthest down in the inheritance tree.

The same idea applies to destructors. If you call delete on b, as above, the compiler will first check if the destructor is virtual in the class hierarchy. In this case, it's not. Therefore it will inspect B's definition, as the variable is of type B*. It'll find the destructor, and call it. After that, the compiler will generate code which calls all parent classes' destructors. In the case of the variable a, the compiler will, as earlier, see that the destructor is not virtual, and will therefore look into A's definition for the destructor (a is of type A*). The compiler will then generate code which calls A::~A(), and nothing more. You can easily understand that this is a problem, if B::B() did stuff like new ....

Two analogies: virtual destructors are like doubly linked lists; you can always find the end of the list from any node in the list - meaning that the compiler will always call the destructor furthest down the inheritance tree, and then work its way back to the root. Non-virtual destructors are like singly linked lists; you can not find the end of the list from all nodes in the list - meaning that the compiler can't call the destructors which comes "after" the class in question.

The golden rule: virtual methods are virtual, if and only if, the first declaration is declared as virtual.

--
Transmitido en Martian en SAP

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