C / C++ / MFC

VC++ 6 Reading MS Excel fields

1-Mar-09 21:59

sunilkumar.d wrote:
My project consists of 15 files in which i need to convert 4 files
in to a library.

That should be doable. So long as the files are in separate source files, you should be able to put them in a static library that you link into the application (it's not particularly different from just linking in the object files directly).

sunilkumar.d wrote:
Or do i need to remove those 4 files and built them in to a separate work space as
library and add it to the complete project?

I'd remove those source files from the original project, add a new static library project to the solution and add the source files to that.

Remember that you'll still need to ship the header files that declare the items defined in the source files.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

RDEPTYLTD1-Mar-09 13:53

RDEPTYLTD

1-Mar-09 13:53

Visual C++ and Microsoft Excel

I am working on a project at the moment and have an issue with reading MS Excel 97 ~ 2003 spreadsheets.

My problem relates to the Excel field format of any given field in the spreadsheet, if a field is formatted in Excel to anything other than Text, then I cannot read the data from that field. for example if column A1 is formatted in excel to Text (good data returned) if A2 is formated to a number (a null is returned) if A3 is text (good data is returned), and so on.

The problem seems to be getting my code to understand the format of any particular field, Here is a snipped of my code;

1) I am using the CRecordset class to open and read the Excel spreadsheet. The spreadsheet has
defined name ranges and generally all works just fine (Provided the fields are text formatted).

2)If i use this line of code to first attempt to read what type of data is in a NUMBER field
"recset.GetODBCFieldInfo( m_csaColumnNames.GetAt(i), fieldinfo );"
I get a positive response when i try the different data types
"if(fieldinfo.m_nSQLType == SQL_VARCHAR){AfxMessageBox("SQL_VARCHAR");}"
suggesting its a data type SQL_VARCHAR data type

3) If i then call GetFieldValue to get the info from a field with a switch command

CDBVariant variant;

recset.GetFieldValue( m_csaColumnNames.GetAt(i), variant);

switch(variant.m_dwType)
{
case DBVT_SHORT:{ szValue.Format("%d", variant.m_iVal);
break;
}
case DBVT_LONG:{ szValue.Format("%d", variant.m_lVal);
break;
}
case DBVT_SINGLE:{ if ( variant.m_fltVal == 0.0 )
szValue = "Verify";
else
szValue.Format("%.1f", variant.m_fltVal);
break;
}

case DBVT_DOUBLE:{ if ( variant.m_dblVal == 0.0 )
szValue = "Verify";
else
szValue.Format("%.1f", variant.m_dblVal);
break;
}

case DBVT_DATE:{
szValue.Format("%B %d, %Y",variant.m_pdate );
break;
}

case DBVT_STRING:{ szValue = *variant.m_pstring; //szValue = V_BSTRT( &varValue );//convert BSTR to CString
break;
}

case DBVT_BOOL:{ if(variant.m_boolVal)
szValue = "TRUE";
else
szValue = "FALSE";
break;
}

case DBVT_UCHAR:{ szValue = (char*)variant.m_chVal;
break;
}

case DBVT_NULL:{
szValue = "Error Null"; AfxMessageBox(szValue);
break;
}
default:{
szValue = "\0";
break;
}
}//switch

RESULTS
All fields which are text, return a valid value which is exactly as per the Excel Spreadsheet, all fields which contains numbers or I even tried date formats in excel return DBVT_NULL which is totally useless because the cell has a number in it or a date.

SUMMARY
I have tried to read the data using GetODBCFieldInfo only and then calling the m_ member depending on the type returned which i know to be in the field, but that does not give me anything other than an unsigned short with random values that bear no resemblance to what is in the actual field.

Any help that anyone can offer in regards to solving this problem would be much appreciated and I I can get the entire class working properly I have happy to post it here for all to use.

Thanks in advance for any assistance.

Re: VC++ 6 Reading MS Excel fields

Dmytro Skrypnyk23-Mar-09 11:56

Dmytro Skrypnyk

23-Mar-09 11:56

Perhaps this library for reading Excel files in C++ will be able to help you - http://www.libxl.com

C++ reads utf-8 xml file

Member 47565741-Mar-09 11:52

Member 4756574

1-Mar-09 11:52

I'm using fread to read a xml file with utf-8 encoding. I set up Mutil-byte character set in VS2005. Now there are several 2 bytes unicode characters inside the file and the program is using char*. The progam reads the file quite OK, only when it encounts those unicode, it seems each 2 bytes unicode characters are sperated into 2 chars, and becomes unreadable character each. I just wonder how this could happen? And is there any way to solve this problem?

Re: C++ reads utf-8 xml file

Sarath C1-Mar-09 17:36

Sarath C

1-Mar-09 17:36

See a similar thread.[^] Hope it helps.

-Sarath.
"Great hopes make everything great possible" - Benjamin Franklin

My blog - Sharing My Thoughts

GetShortPathName

tom groezer1-Mar-09 9:54

tom groezer

1-Mar-09 9:54

I have an application which uses the win API GetShortPathName to get the short path(8.3) from a long path.
The string is terminated with a '\'. Yet the path returned is not a short path. Is there any association with the registry key NtfsDisable8dot3 or does anyone have any idea as to what could be the reason of its not working. The platform is windows 2003.

Re: GetShortPathName

Stuart Dootson1-Mar-09 10:09

1-Mar-09 10:09

tom groezer wrote:
Is there any association with the registry key NtfsDisable8dot3

Yes - the first Google hit for 'NtfsDisable8dot3'[^] could have told you that.

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Re: GetShortPathName

tom groezer1-Mar-09 21:08

tom groezer

1-Mar-09 21:08

Is there any other reason for such behavior

Re: GetShortPathName

Stuart Dootson1-Mar-09 21:55

Re: Stupid Menu Question [modified]

1-Mar-09 21:55

For starters:

The filesystem on which the file resides does not support short filenames (so, NTFS with the registry key we talked about, HFS+, extfs via a network connection)
The file doesn't exist - it has to for GetShortPathName to work

Did you check the extended error information (with GetLastError) to see what error was signalled?

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Stupid Menu Question

Mats Selen1-Mar-09 8:19

Mats Selen

1-Mar-09 8:19

I have written a small C++ program using Visual Studio 2008. I use the resource editor to create some menus and then look for the appropriate events in the callback routine to perform whatever action is needed when a certain menu item is selected (part of the callback routine is below):

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam) {
int wmId;
switch (message) {
case WM_COMMAND:
wmId = LOWORD(wParam);
// Parse the menu selections:
switch (wmId) {
case ID_TOOLS_INITIALIZECOMPORT:
SetupStuff();
initialized = true;
break;
case ID_TOOLS_CALIBRATE:
reCalibrate();
break;
...

I'd like to know how to modify the properties of the menu items from the code (for example changing the text or setting a check-mark etc) but since I used the resource editor to create the menus I don't know how to get their handles or how to access their properties - all I know for each menu item is its ID.

I'm sure I'm just being stupid but any advice would be greatly appreciated.

Mats

Stuart Dootson1-Mar-09 10:06

1-Mar-09 10:06

If it's the same as the sample I just created, you specify the menu in the window class:

ATOM MyRegisterClass(HINSTANCE hInstance)
{
	WNDCLASSEX wcex;

	wcex.cbSize = sizeof(WNDCLASSEX);

	wcex.style			= CS_HREDRAW | CS_VREDRAW;
	wcex.lpfnWndProc	= WndProc;
	wcex.cbClsExtra		= 0;
	wcex.cbWndExtra		= 0;
	wcex.hInstance		= hInstance;
	wcex.hIcon			= LoadIcon(hInstance, MAKEINTRESOURCE(IDI_XX));
	wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
	wcex.hbrBackground	= (HBRUSH)(COLOR_WINDOW+1);
	wcex.lpszMenuName	= MAKEINTRESOURCE(IDC_XX);
	wcex.lpszClassName	= szWindowClass;
	wcex.hIconSm		= LoadIcon(wcex.hInstance, MAKEINTRESOURCE(IDI_SMALL));

	return RegisterClassEx(&wcex);
}

To get the menu for a window of this class, use GetMenu[^] using the window handle.

[edit]Here's a sample commnd handler (insert in a switch statement like the one you have in your post) that inverts the checked state for a menu item (ID_FILE_TESTITEM) when the menu item is selected. This does assume that the File menu is the first sub-menu on the menu bar.

case ID_FILE_TESTITEM:
   {
      HMENU menu = GetMenu(hWnd);
      menu = GetSubMenu(menu, 0);
      const bool checked = (GetMenuState(menu, ID_FILE_TESTITEM, MF_BYCOMMAND)&MF_CHECKED)==MF_CHECKED;
      CheckMenuItem(menu, ID_FILE_TESTITEM, MF_BYCOMMAND | (checked?MF_UNCHECKED:MF_CHECKED));
   }

[/edit]

PS - any reason you're using raw C/C++ rather than a framework (WTL or MFC)? They do make it easier to do all this, honest Smile | :)

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

modified on Sunday, March 1, 2009 4:25 PM

Mats Selen1-Mar-09 10:47

Mats Selen

1-Mar-09 10:47

Thanks!! That worked and was just what I needed!

As to why I'm doing it this way - I basically don't know any better. I am rather new to windows programming (lets just say that I learned FORTRAN using punch cards). The application I am writing is controlling some hardware so until today I was more focused on just getting the code to talk to serial ports and didn't want to try learning anything else at the same time. As long as we are on that topic, though, can you recommend a good book (or other resource) for someone starting out with MFC or WTL - something with decent examples that an old fart used to programming in vanilla C can understand Smile | :)

Stuart Dootson1-Mar-09 11:29

1-Mar-09 11:29

Mats Selen wrote:
As to why I'm doing it this way - I basically don't know any better. I am rather new to windows programming

Fair enough

Mats Selen wrote:
can you recommend a good book (or other resource) for someone starting out with MFC or WTL - something with decent examples that an old fart used to programming in vanilla C can understand

For WTL - Michael Dunn's article series on this site[^] is good.

For MFC - mmmmm, not sure. I started MFC programming over 10 years ago, when there were still MFC books around. I think it was an earlier version of this book[^]. If you have a Safari[^] subscription, that's on there.

Apart from that, best I can suggest is Google and possibly this[^]?

Java, Basic, who cares - it's all a bunch of tree-hugging hippy cr*p

Richard Andrew x641-Mar-09 13:22

Richard Andrew x64

1-Mar-09 13:22

Programming Windows with MFC - Second Edition
by Jeff Prosise

http://www.amazon.com/Programming-Windows-Second-Jeff-Prosise/dp/1572316950/[^]

template and vector [modified]

Mats Selen2-Mar-09 1:40

Mats Selen

2-Mar-09 1:40

Thanks - you guys make this a great forum!

transoft1-Mar-09 7:24

1-Mar-09 7:24

Hi

I want to use vector to save following struct. It it possible?

template <class t="">
struct Cell
{
T Val;
};

vector <<cell>> vname ?????

What is the best solution for it?

Thanks,

modified on Sunday, March 1, 2009 1:49 PM

Code-o-mat1-Mar-09 7:59

1-Mar-09 7:59

For example:

template <typename T>
struct Cell
{
  T Val;
};
#define CELL_TEMPLATE(type)   Cell<type>
std::vector<CELL_TEMPLATE(int)> my_cell_vector;

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

transoft1-Mar-09 8:14

1-Mar-09 8:14

Thank you very much for your reply. I want to use one vector to save different data type of data. How can I do it?

Best,

Code-o-mat1-Mar-09 8:18

1-Mar-09 8:18

What exactly do you mean by "save"?

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

transoft1-Mar-09 8:22

1-Mar-09 8:22

like following:

Cell<int> typeint;
typeint.Val = 1;
recVec.push_back (typeint);

Cell<float> typefloat;
typefloat.Val = (float) 1.111;
recVec.push_back (typefloat);

Code-o-mat1-Mar-09 8:43

1-Mar-09 8:43

Well, if the structure isn't too complex, you could simply use a union and some way to signal what type your struct is actually holding. Something like:

#define STRUCT_TYPE_FLOAT   1
#define STRUCT_TYPE_DOUBLE   2
#define STRUCT_TYPE_INT  3
...
struct Cell
{
public:
  short typeFlag;
  union {
    float   valFloat;
    double  valDouble;
    int     valInt;
    ...
  };
};
...
std::vector<Cell> my_vector; 
Cell cell_double;
cell_double.valDouble = 1.23;
cell_double.typeFlag  = STRUCT_TYPE_DOUBLE;
my_vector.push_back(cell_double);
Cell cell_int;
cell_int.valInt = 123;
cell_int.typeFlag = STRUCT_TYPE_INT;
my_vector.push_back(cell_int);
...

If it's a bit more complex than that then you should rather use pointers, something like this:

class CellBase
{
  virtual ~CellBase()
};
template<typename TType>
class Cell: public CellBase
{
  ...
};
std::vector<cellbase> my_vector;
my_vector.push_back(new Cell<int>(123));  //Don't forget to delete the Cells somewhere later...

These are far from complete implementations of anything, just "skeletons"...

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

transoft1-Mar-09 8:45

1-Mar-09 8:45

Thank you very much,

Code-o-mat1-Mar-09 9:08

1-Mar-09 9:08

Hmm, this is strange, i got a new notification of you posting something here, i click the link in the email, it brings me to this page but your message does not appear. I already got one of these once, maybe it is some caching problem, or something i don't yet know about the forums. Anyways, the email itself contains your post so here's an answer to that: in your CCellBase, make the destructor public.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Life: great graphics, but the gameplay sux. <

transoft1-Mar-09 9:50