Managed C++/CLI

13-Jul-06 1:43

Hi
I have a project where by I define a pre-processor variable entitled PROEDITION. In the project where I define this variable some .cpp files seem to understand that the variable PROEDITION has been defined. Unfortunately one of the most important .cpp files does not seem to pick up this pre-processor variable. Is there a reason why this would happen? It's not just this pre-processor variable, it could be any of them that I define at project scope. It just seems that one of my .cpp files does not understand the pre-processor variables at all.

Any help on this would be appreciated.

Dave

Jun Du13-Jul-06 2:10

13-Jul-06 2:10

Where did you define PROEDITION?

Best,
Jun

Dave_Roach13-Jul-06 3:08

Re: VC7 Preprocessor variables not working. [modified]

13-Jul-06 3:08

I defined PROEDITION in the Pre Processor Definitions

WIN32;_DEBUG;_WINDOWS;_USRDLL;PROEDITION

That is what is in there currently.

Dave

test

Sebastian Schneider13-Jul-06 22:09

Sebastian Schneider

13-Jul-06 22:09

Is the last separator a ":" or a ";"? I am asking because there is a smiley there and I am not sure if this forum uses Poke tongue | ;-P

(thats a test - Semicolon P) as a smiley or :P (another test - Colon P) or maybe both.

Edit: OK. It uses both.
Worth a try, though.

*Test ends*

Jonathan [Darka]13-Jul-06 4:10

Jonathan [Darka]

13-Jul-06 4:10

Is there a possible redefinition / undef of the same variable in that .cpp file ?

Darka [Xanya]

Dave_Roach13-Jul-06 4:57

13-Jul-06 4:57

no unfortunately not.. It just seems to be ignoring anything that I put in as a preprocessor variable.

Jonathan [Darka]13-Jul-06 5:10

Jonathan [Darka]

13-Jul-06 5:10

bugger, i suppose you've checked spelling, etc.

Darka [Xanya]

Dave_Roach13-Jul-06 5:20

cannot convert void * to System::Data::DataColumn

13-Jul-06 5:20

Yeah, it's the wierdest thing. I mean it uses precompiled headers via stdafx.h

I am not sure why this is not working. The other thing that is sort of unique is that the MIDL compiler has a preprocessor variable as well. I don't think that should matter though, but I am pretty sure that is rare.

The IDL is compiling correctly though with the preprocessor doing what it should.

arvindbhateja13-Jul-06 1:04

Re: cannot convert void * to System::Data::DataColumn

13-Jul-06 1:04

Can anyone tell me how can I overcome the following error:

Error 39 error C2440: '=' : cannot convert from 'void *' to 'System::Data::DataColumn ^'

Here is the code which is generating error:

CPtrList* MYpclFields; // this is working fine
POSITION MYposField; // is having the right value
DataColumn^ pColumnInfo; // System::Data::DataColumn object
...
...
...
pColumnInfo = MYpclFields->GetNext (MYposField); // error lies here

actually GetNext() fn. returns a (void *) and I want to convert that into (DataColumn^).

Plz... D'Oh! | :doh:

Thanks...

Jun Du13-Jul-06 2:09

Re: cannot convert void * to System::Data::DataColumn [modified]

13-Jul-06 2:09

Handle (^) and pointer (*) are not castable. The former is managed; the latter is unmanaged.

Best,
Jun

arvindbhateja13-Jul-06 2:29

Re: cannot convert void * to System::Data::DataColumn

13-Jul-06 2:29

What should I do to get rid of it?

I need to convert void* to System::Data::DataColumn^

It's very important.

-- modified at 8:32 Thursday 13th July, 2006

Eariler I converted managed (^) to unmanaged (*)

pclFields->AddTail ((void *) pclFieldInfo);

Where pclFiledInfo is of type DataColumn^ and it's working perfectly fine.

Jun Du13-Jul-06 3:52

Re: cannot convert void * to System::Data::DataColumn

13-Jul-06 3:52

Handle(^) walks through the managed heap, while pointer(*) walks through the unmanaged heap. They don't see eye to eye.

arvindbhateja wrote:
I need to convert void* to System::Data::DataColumn^

You can't.

arvindbhateja wrote:
Eariler I converted managed (^) to unmanaged (*)

pclFields->AddTail ((void *) pclFieldInfo);

This is wrong. By doing so, you may have corrupted GC (garbage collection) on the managed heap. On the other hand, the managed C++ provides a mechanism to pin an object on the managed heap. The pinning is a process to temporarily keep the contant address of an object on the managed heap. Here is some sample code extracted from the C++/CLI spec:

void f(int* p) { *p = 100; } 
int main() { 
 array<int>^ arr = gcnew array<int>(100); 
 pin_ptr<int> pinp = &arr[0]; // pin arr s location 
 f(pinp); // change arr[0] s value 
}

You could consider this as a temporary "conversion" from managed to unmanaged. But I'm not aware of any "conversion" in the reverse direction.

Best,
Jun

arvindbhateja13-Jul-06 4:00

Re: cannot convert void * to System::Data::DataColumn

13-Jul-06 4:00

Thanks for the response.

Is there any alternate to CPtrList which I can use in C++/CLI?

Jun Du13-Jul-06 4:55

Re: cannot convert void * to System::Data::DataColumn [modified]

13-Jul-06 4:55

Yes, there are a whole bunch of collection tyeps you can choose from: link.

Best,
Jun

arvindbhateja13-Jul-06 5:00

Re: cannot convert void * to System::Data::DataColumn

13-Jul-06 5:00

Thanks for replying.

If I don't get a solution then I'll have to rewrite a very big logic. Actually I'm migrating an application from VC6 to VC8.

Frown | :(

Jun Du13-Jul-06 6:02

Re: cannot convert void * to System::Data::DataColumn

13-Jul-06 6:02

Hopefully, you don't need to write much logic. CPtrList is just a pointer list (MFC class). It can be easily replaced by a simple list (.NET class), which stores a pointer to a node.

Best,
Jun

arvindbhateja13-Jul-06 23:45

Re: cannot convert void * to System::Data::DataColumn

13-Jul-06 23:45

Thanks for helping me so much.

Can u tell me just one more thing - What is the alternate to CMapStringToOb MFC class in C++/CLI. Plz can u suggest me what should I do to write the code in C++/CLI for the code shown below:

<br />
int nCount = clRecSet.GetFieldCount();<br />
	// Th efield count.<br />
    CDaoFieldInfo*  pclFieldInfo;  // Pointer for field info.<br />
    CMapStringToOb  clTables;      // For table.<br />
    CPtrList* pclFields = NULL;     // Pointer list.<br />
       <br />
	for (int ii = 0; ii < nCount; ii++)<br />
	{<br />
		pclFieldInfo = new CDaoFieldInfo;<br />
		clRecSet.GetFieldInfo(ii, *pclFieldInfo, AFX_DAO_SECONDARY_INFO);<br />
        if (clTables.Lookup (pclFieldInfo->m_strSourceTable, <br />
			                  (CObject*&) pclFields)  != TRUE )<br />
        {<br />
            pclFields = new CPtrList;<br />
            clTables.SetAt (pclFieldInfo->m_strSourceTable, pclFields);<br />
        }<br />
        pclFields->AddTail ((void *) pclFieldInfo);<br />
    }<br />
    // Now the fields are grouped together by table name<br />
...<br />
...<br />
<br />
    POSITION pos = clTables.GetStartPosition();<br />
	// Position index.<br />
    while (pos != NULL)<br />
    {<br />
	pclFields = NULL;<br />
        CPtrList*   pclFields;<br />
        CDaoFieldInfo* pFieldInfo;  // The field info.<br />
        <br />
        clTables.GetNextAssoc (pos, strCurrTbl, (CObject*&) pclFields);<br />
        POSITION posField = pclFields->GetHeadPosition();<br />
	int nIndex = 0; // Index for the loop.<br />
        while (posField != NULL)<br />
        {<br />
            pFieldInfo = (CDaoFieldInfo *) pclFields->GetNext (posField);<br />
<br />
.....<br />
            <br />

In the the above code I can replace :

CMapStringToOb -> ?
CPtrList -> ArrayList
CDaoFieldInfo -> DataColumn (Problem with fetching the database table name not the table name which comes from dataset object)

In DataColumn I can't get the name of the table, the column actually belongs to as we can do in CDaoFieldInfo::m_strSourceTable. Actually I've to map the name of the table with it's corresponding column and put that into a CMapStringToOb object.

Jun Du14-Jul-06 8:38

Moving the DrawnRectangle with mouse on the Form [modified]

14-Jul-06 8:38

CMapStringToOb doesn't seem to have a counterpart in .NET collection classes. It looks you have some work to do.

Best,
Jun

Nagaraju_Focus12-Jul-06 19:36

Nagaraju_Focus

12-Jul-06 19:36

in VC++.Net I have drawn a Rectangle on the form.

My task is ,when i keep the cursor on Rectangle and (move the Mouse + Mouse Left Button Down) it should move accordingly.

Suggest me..

Thanks In Advance

Bye....

Nagaraju

-- modified at 7:58 Thursday 13th July, 2006

Re: Moving the DrawnRectangle with mouse on the Form

Jun Du13-Jul-06 2:03

Re: Moving the DrawnRectangle with mouse on the Form

13-Jul-06 2:03

You should handle some of the mouse events such as MouseEnter, MouseDown, MouseUp, MouseMove and MouseLeave.

Best,
Jun

Nagaraju_Focus13-Jul-06 23:02

Nagaraju_Focus

13-Jul-06 23:02

that is not my problem.
I have drawn Rectangle On the Form Using Graphics Class.

My code is

Graphics ^gr=this->CreateGraphics();
gr->DrawRectangle(gcnew Pen(Color::Black),90,50,60,60);
and when I keep the mouse on drawn Rectangle
MouseMove+LeftClickMOuse ,the rectangle should move accordingly

plz suggest me

Nagaraju

Re: Moving the DrawnRectangle with mouse on the Form

Jun Du14-Jul-06 2:10