Icons with shortcut layers - C / C++ / MFC Discussion Boards

Axter19-Sep-02 3:07

19-Sep-02 3:07

The questioner was asking about a member function pointer.
You can not use a static member function with a member function pointer.

You can however, use a function pointer with a static member function.

Function pointers and member function pointers are two different things, and you can't mix them.

Re: Pointer to class memeber func

Axter18-Sep-02 18:07

Axter

18-Sep-02 18:07

(m_Obj.*m_Func)()

Try the following:
MyClass()
{
m_pMethod = voidMethod; //OK
(*m_pMethod)();
}

To use function pointers you have to use some funcky looking syntax.
If you're calling the function from inside your class, just prefix the pointer with an asterick, and wrap perantesise around it:
(*MyFunPtr_Array)();

If you're doing it out side of the class, you would use the following syntax:
(MyClassVar.*m_Func)();

Re: Pointer to class memeber func

BlackSmith19-Sep-02 2:59

BlackSmith

19-Sep-02 2:59

Axter wrote:
Try the following:

MyClass()<br />
{<br />
m_pMethod = voidMethod; //OK<br />
(*m_pMethod)(); <font color=red>//NOT so OK:<br />
Error1: error C2171: '*' : illegal on operands of type 'void (__thiscall MyClass::*)(void)'<br />
Error2: error C2064: term does not evaluate to a function<br />
</font>}

Whattodo?????

--BlackSmith--
/*The roof is on fire, we don't need no water, let the MF burn*/. BHG.

Re: Pointer to class memeber func

Axter19-Sep-02 3:02

Axter

19-Sep-02 3:02

I tested the proposed solution I gave you on VC++, and for some reason it doesn't like the syntax without the class prefix.
If you're using VC++, try the following instead:

class MyClass
{
public:
typedef void (MyClass::* MyClassMethodPtr)();
MyClassMethodPtr m_pMethod;
MyClass()
{
m_pMethod = voidMethod; //OK
((*this).*m_pMethod)();
}

void voidMethod()
{
//Do do do, boo boo boo...
printf("Hello World");
}
};

Re: Pointer to class memeber func

BlackSmith19-Sep-02 6:09

BlackSmith

19-Sep-02 6:09

Thanks man, this works (For real?! for sure!) Laugh | :laugh:

--BlackSmith--
/*The roof is on fire, we don't need no water, let the MF burn*/. BHG.

i want some lesson for dynamic declaration

CHEICKNA TRAORE18-Sep-02 12:11

CHEICKNA TRAORE

18-Sep-02 12:11

Hi,

I have an array like this :

char sArray[4][5];

I want to declare this array with new or malloc like this :

char** sArray=NULL;<br />
sArray = new char[20];<br />
or sArray = (char*)malloc(20);

Can anybody help me to write correct declaration

Thanks in advance

Re: i want some lesson for dynamic declaration

C^hris L^osinger18-Sep-02 12:14

C^hris L^osinger

18-Sep-02 12:14

there is no simple way to do it in C++.

you will have to do something like this:

// alloc an array of arrays
int ** array = new int* [sizex];
for (int i = 0; i < sizex; ++i)
    array[i] = new int[sizez];

-c

"Half of the harm that is done in this world is due to people who want to feel important."
-- TS Elliot

Icons with shortcut layers

CaesarCZ18-Sep-02 11:55

CaesarCZ

18-Sep-02 11:55

Hi,
I've made a bad choice in implementing the icon retrieving code in my code. But's hardcoded now and would be toough and bug producing to make any really major corrections now.

So anyway, the question: I need to get the icon of some file (SHGetFileInfo), but with shortcut overlay (or shared overlay, but this is not neccessary), for both 16x16 and 32x32 icons. In other words, a image list that would contain both "shortcuted" and standard icons.

Thanks in advance

Re: Icons with shortcut layers

Michael Dunn18-Sep-02 12:00

Michael Dunn

18-Sep-02 12:00

Add the SHGFI_LINKOVERLAY flag to your SHGetFileInfo call. Smile | :)

--Mike--
Just released - RightClick-Encrypt v1.4 - Adds fast & easy file encryption to Explorer
My really out-of-date homepage
Sonork-100.19012 Acid_Helm

Unicode to Arabic 1256

Hadi Rezaee18-Sep-02 11:43

Hadi Rezaee

18-Sep-02 11:43

Hello there,

How can i convert my Unicode string to Arabic 1256 codepage ?

Arabic 1256 is ANSI ???

I mean for solving my problem i must convert Unicode characters to ANSI ??

My month article: Game programming by DirectX by Lan Mader.
Please visit in: www.geocities.com/hadi_rezaie/index.html

Hadi Rezaie

CRT .dll's for Winsock

Aaron Schaefer18-Sep-02 11:13

Aaron Schaefer

18-Sep-02 11:13

Hi All,

I've been having weird heap breakpoints show up in an app that is using the winsock 2 library, and have heard that this may be related to the version of the C runtime libraries I am linking with. Anybody know which version is the corrcet one to use with the winsock libraries? Multithreaded, Single Threaded, Multithreaded .dll?

Thanks

Aaron

Passing strings from VC to a VB COM dll

ns18-Sep-02 11:11

18-Sep-02 11:11

My VB function signature is:

Public Function MakeDB(txtFilename As String, dataBaseName As String)

I will pass these two parameters from VC as:

CString dbName, myFile;

     edit1.GetWindowText(dbName);

     edit2.GetWindowText(myFile);

     ptr->MakeDB(myFile, dbName)

What I need to know is can I do this or do CStrings and VB strings differ. if so, how to pass these strings to the VB dll?

Thanks,
ns

Re: Passing strings from VC to a VB COM dll

ns18-Sep-02 11:28

18-Sep-02 11:28

Well, I did what I said above, and got the VC compile error:

C:\msway\mswayView.cpp(174) : error C2664: 'MakeDB' : cannot convert parameter 1 from 'class CString' to 'unsigned short ** '

with:

ptr.CreateInstance(__uuidof(Class1));
 ptr->MakeDB(strFile,dataBaseName);

on the VC side

and

Public Function MakeDB(txtPMAFilename As String, dataBaseName As String)

on the VB side.

Help!!

Thanks,
ns
(ps. I am going to convert my CStrings into char * but dont know if that will do it...)

Re: Passing strings from VC to a VB COM dll

ns18-Sep-02 11:35

18-Sep-02 11:35

Nope. this time with char* passed into VB, I got the compile error in VC:

C:\Trainer\A_TR NOBlob inDB series\VBDBDll2\msway\mswayView.cpp(185) : error C2664: 'MakeDB' : cannot convert parameter 1 from 'char *' to 'unsigned short ** '

Now what to try?

Thanks,
ns

Re: Passing strings from VC to a VB COM dll

Bart Robeyns18-Sep-02 12:12

Bart Robeyns

18-Sep-02 12:12

The short answer:place a call to SysAllocString around your char*.
The longer one: Strings in COM are not 'char*' , but 'BSTR', which is a length-prefixed, wide-character string. Furthermore, allocation of these BSTR must be handled by the COM runtime, you are not allowed to do it yourself. SysAllocString() allocates a block of memory to hold the string you passed it, converted to a widestring and returns a pointer to this memory-block. You can use that pointer as an argument in your method-call.
When your finished with the BSTR, you should call SysFreeString() on it.
If you're going to use COM from C++, you will save yourself a lot of trouble by reading some initiating articles, like Beginner's Tutorial: Calling Visual Basic ActiveX DLLs from Visual C++ here at The Code Project.

Re: Passing strings from VC to a VB COM dll

ns_18-Sep-02 13:50

ns_

18-Sep-02 13:50

Thanks. I was following the article from CP and got MIDL compiler errors so gave up. I see that hes just passing a _bstr_t. I'll have to convert the GetWindowText(pathName) to a _bstr_t. You say that allocation has to be done by the COM runtime, yet the article just passes in a _bstr_t. I'm probably missing something here. Thanks very much for the response. I get to try it tomorrow.

Re: Passing strings from VC to a VB COM dll

Anonymous18-Sep-02 21:08

Anonymous

18-Sep-02 21:08

_bstr_t, just like CComBSTR mentioned in another reply, is a wrapper object around BSTR that handles allocation and destruction transparently. In other words, you can use without knowing the details.

Re: Passing strings from VC to a VB COM dll

ns19-Sep-02 1:19

19-Sep-02 1:19

I tried your method and still got the compile error:

C:\msway\mswayView.cpp(169) : error C2664: 'SysAllocString' : cannot convert parameter 1 from 'char *' to 'const unsigned short *'

My VB dll function that I'm passing to has the signature:

Public Function MakeDB(txtPMAFilename As String, dataBaseName As String)

and I just tried:

  CString dataBaseName0 = "C:\\Image.mdb";

  CString strFile0 = "C:\\Trainer\\final1.txt";

  char* dataBaseName = new char[dataBaseName0.GetLength() +1];

  strcpy(dataBaseName, dataBaseName0);

  <code>_bstr_t b_dataBaseName = SysAllocString (dataBaseName);</code>

   char* strFile = new char[strFile0.GetLength() +1];

  strcpy(strFile, strFile0);

<code>  _bstr_t b_strFile = SysAllocString (strFile);</code>

   //short st1;
  // Declare the Interface Pointer for your Visual Basic object. Here,
  // _Class1Ptr is the Smart pointer wrapper class representing the
  // default interface of the Visual Basic object.

  _Class1Ptr ptr;
  // Create an instance of your Visual Basic object, here
  // __uuidof(Class1) gets the CLSID of your Visual Basic object.

   ptr.CreateInstance(__uuidof(Class1));

    <code>ptr->MakeDB( b_strFile, b_dataBaseName);</code>

    SysFreeString (b_dataBaseName);

    SysFreeString (b_strFile);

Re: Passing strings from VC to a VB COM dll

Bart Robeyns19-Sep-02 11:21

Bart Robeyns

19-Sep-02 11:21

This is all you'll be needing:

_bstr_t b_dataBaseName = "C:\\Image.mdb";
_bstr_t b_strFile = "C:\\Trainer\\final1.txt";
_Class1Ptr ptr;
ptr.CreateInstance(__uuidof(Class1));
ptr->MakeDB( b_strFile, b_dataBaseName);

I have given the impression that it was SysAllocString takes a char* and converts it to a widestring. That is not true. Sorry for that.
In the above code, the _bstr_t does all the work for you:
- it converts the char* to wchar_t*
- it makes calls to SysAllocString() and SysFreeString() when needed

So there's no need to make calls to SysAllocString yourself when using a _bstr_t.

Final question...I hope

ns19-Sep-02 11:37

19-Sep-02 11:37

Great! Thanks. Now the only remaining thing to iron out in this issue is that the VB dll functions argument had to be changed to MyFunc(ByVal as String) or it wouldnt compile. This seems to indicate that I cant pass in a _bstr_t that I want modified by the dll and have the changes persist in the VC - I mean by passing in the _bstr_t by reference. Like if I wanted the VB dll to fill in myBstrString, I'd call it like:

ptr->FillString(&myBstrString)

pls correct me here if I am wrong in calling it like this to get what I want

and in the VB dll

Function FillString(ByRef a as String)

a ="filledByVB"

I'd really appreciate if you can let me know if I'm understanding this pass by reference notion correctly (esp on the VC side - maybe I dont need that & in the ptr call, do I? If the argument was an int or something, I know for sure we'd need to pass in &myInt, and the & would be necessary )

Anyways the time the compiler was unhappy was when the dl had ByRef and I sent in the _bstr_t like this:

ptr->FillString( myBstrString);

Thanks,
ns

Re: Passing strings from VC to a VB COM dll

Michael Dunn18-Sep-02 12:02

Michael Dunn

18-Sep-02 12:02

VB uses BSTRs I believe, so use temporary CComBSTR variables in your call:

ptr->MakeDB ( CComBSTR(LPCTSTR(myFile)), CComBSTR(LPCTSTR(dbName)) );

--Mike--
Just released - RightClick-Encrypt v1.4 - Adds fast & easy file encryption to Explorer
My really out-of-date homepage
Sonork-100.19012 Acid_Helm

Re: Passing strings from VC to a VB COM dll

ns_18-Sep-02 13:52

ns_

18-Sep-02 13:52

That looks like a cool solution. MAny many thanks. Smile | :)

Re: Passing strings from VC to a VB COM dll

ns19-Sep-02 1:03

19-Sep-02 1:03

Unfortunately the compiler didnt like the CComBSTR either...
Thanks anyways.
ns

GUI front end

WhiteLegend18-Sep-02 10:57

WhiteLegend

18-Sep-02 10:57

Hi,
I've been programming in VC++ for a while now and I'm pretty good at it, but I've only been dealing with the coding aspect C++. Now I want to make a GUI front end for the programs I wrote. Where can I learn about making a GUI front end for VC++? Is there a place where I can download really simple sample code and programs? Thanks in Advance

Re: GUI front end

Ravi Bhavnani18-Sep-02 11:05

Ravi Bhavnani

18-Sep-02 11:05

WhiteLegend wrote:
Is there a place where I can download really simple sample code and programs?
Um... yes, it's called CodeProject.

/ravi

Let's put "civil" back in "civilization"
http://www.ravib.com
ravib@ravib.com

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