mfc, CString Problem !!!

1. Migration to VC7: CString problem

2. Cstring problem VS.Net 2003

I am writing a MC++ wrapper for a native dll, that will be called by C# 
applications.

One of the functions returns a CString parameter: 

long GetProductStringDescriptor(int DevID, CString& sDescriptor) 

My wrapper accepts a ref to a managed string (below) and needs to pass this 
into to function so it is changed and returned. 

GetProductStringDescriptor(int DevID, String __gc* __gc* StringDesc) 

The problem I'm finding is that I get "Object not set to an insatance of an 
object" errors when I call the unmanaged function. I have tried passing a 
CString and String* into the function and converting it back to be returned. 
Both of these options cause the error.

I have tried all the MSDN solutions on mixed dll's, and this has not helped.

Any help would be gratefully received.

3. CString problem

4. unsigned char* to CString - problem

How to convert unsigned char* to CString:

I have some data and wrote some function to convertion data to CString
and dispay it:
e.g.
u_char_[0] =10;
u_char_[1] =100;
u_char_[2] ='A';
u_char_[3] ='\0';

Convert_to_CS(u_char_);

****
void Convert_to_CS (unsigned char* u_char){

CString str0;

str0.Format("%d",u_char[0]);
AfxMessageBox ("First:" +str0);

CString str(u_char);
AfxMessageBox ("Second:" +str);

}

***

Output:
First: 10  //good
Second:  // so nothing, why ??

Why working only first convetion ? I want convert whole array of uchar,
how to do it ?
When I  declare on input:
unsigned char u_char[] ="abcdef" then works good and display :
Second: abcdef
but I must put data individually for each byte...

5. UNICODE CString problem

6. CString problem

Chung, you might want to consider using the CStringList class instead
of developing your own linked list.  Or if you want more than just a
single CString in each item, use CPtrList (or CObList). For instance:

class CContentData {
public:
    CString  Title;
    CString  Content;
};

then in program:

  CPtrList  ContentList;

  CContentData	*p = new CContentData;

  p->Title = "Test";
  p->Content = "this is a test";
  ContentList.AddTail (p);

  ... add some more

then to extract:

  POSITION pos = ContentList.GetHeadPosition ();
  while (pos) {
    CContentData  &Ct = *(CContentData*) ContentList.GetNext (pos);
  }

or you can use GetTailPosition and GetPrev instead of GetNext.

I usually build my own list class to reduce the casting and
automatically clean up the items in the list, like this:

class CContentList : public CPtrList {
public:

  ~CContentList () { RemoveAll (); }

  CContentData*  GetNext (POSITION& p)
  { return (CContentData*) CPtrList::GetNext (pos);

  CContentData*  RemoveTail ()
  { return (CContentData*) CPtrList::RemoveTail (); }

  void  RemoveAll () { while (! IsEmpty ()) delete RemoveTail (); }
};

Then the program code reduces to:

to extract:

  POSITION pos = ContentList.GetHeadPosition ();
  while (pos) {
    CContentData  &Ct = *ContentList.GetNext (pos);
  }

This way the program code is cleaner and when you exit the routine (or
delete your CContentList class instance) the list is automatically
disposed.  And you can also add other useful functions to your list
class, such as Find, insert (in order), Sort, operator=, operator==,
etc.

Hope this was helpful.

Russ



On Tue, 22 Jul 2003 18:45:01 +0800, Chung < XXXX@XXXXX.COM >
wrote:

>It works perfects to me!
>thanks Scott.
>I'm used to write Ansi C rather visual C++.
>
>Scott McPhillips wrote:
>
>> Chung wrote:
>> 
>>>I want to make a link list of a struct included a CString member.
>>>in the .h file i declare:
>>>
>>>-----------------------------------------------------
>>>struct items{
>>>        struct items * next;
>>>        struct items * prev;
>>>        CString title;
>>>        CString content;
>>>};
>>>typedef struct items Items;
>>>-------------------------------------------------------
>>>
>>>and when i use it,
>>>i tried :
>>>Items *node;
>>>node = (Items*)malloc(sizeof(Items));
>>>node->content = (CString)"testing\n";
>>>
>>>however i got the following message:
>>>Assertion Failed: vixo: File afx.inl, Line 124
>>>
>>>also , i tried the followings but still error:
>>>1)
>>>CString temp = "testing\n";
>>>node->content = temp;
>>>2)
>>>CString temp("testing\n");
>>>node->content = temp;
>>>
>>>how can i fix the problem? thanks
>> 
>> 
>> When programming in C++ forget you ever heard of malloc.  Use 'new'.  It
>> properly initializes C++ objects by invoking their constructor and the
>> constructors of all embedded members.  Also the cast to (CString) is an
>> error. But alternatives 1 and 2 are OK, and even simpler is
>> node->content = "testing\n";
>> 
>> --
>> Scott McPhillips [VC++ MVP]
>

7. Weird CString problem

8. CString problem!!!

This is my code.
#include <iostream>
#include "atlstr.h"
using namespace std;
int main()
{
    char *orig = "Hello, World!";
    CString cstring(orig);
    cout << orig << endl;
    cout << cstring << endl;
}

My compiler is Visual Studio 2005.
The output is;
Hello, World!
001551A0

Why 001551A0 instead of Hello, World! ?

Anybody knows why. PLEASE tell me.