returning variant array from vb to vc++

Posted: 2002-06-01
By: ArchiveBot
Viewed: 69

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VB6 Code Cache

Passing variant array between vb server and vc++ is noteasy task. I found a technique when i searched for a week on this matarial - how to return variant array from activeX exe(VB) to MFC(VC++).To make easy you , i submit not in exact form what i found on msdn and internet ,but what technique i used and got success.

Original Author: Ashutosh Upadhyay

Code

How to return variant array from VB ActiveX Server (EXE/DLL) to VC++

Step 1. Make a VB ActiveXDll /EXE project

   1.1 - Name your Project and Default Class , We assume Prject name - Project1 and      Class Name - Class1

   1.2 copy and past follwoing function
     public function abc() as Variant
     dim a(10) as long
     a(0) = 10
     a(1) = 13
     .  
     . 
     .
     a(10) = 67
    end function
   1.3  open file menu ,choose make project1.dll/project1.exe 
Step 2. Open A Simple VC++ Project
   2.1 choose MFC application(exe),then,dialog application,then,support automation
   2.2 choose View -> ClassWizard -> Automation tab -> Press Add Class ->     choose From a type library
   2.3 allow MFC to generate wrapper classes for your VB server. We assume name     of Wrapper class genrated by MFC is _Class1
   2.4 in your dialog class ( in ..dlg.h file) , make a variable of your wrapper class
      class YourApplictionDlg : public CDialog
      {
      ..........
      ............
      public :
      _Class1 ashu;
      ...............
     ................
      ............
      };
 
     2.5 open Oninitdialog() function of your dialog (dlg) class and copy following       code in the end of function
      // TODO: Add extra initialization here
      ashu.CreateDispatch("Project1.Class1");
      return TRUE;
    2.6 To retrieve the values of array of VB server write followoing code 
       in a function, for example in OnOK()

void .......Dlg::OnOK() {
 VARIANT v;
 v = ashu.abc();
 
 SAFEARRAY *parray;
 parray = v.parray;
 
short sElem;
long lLb, lUb, l;
long lResult[10];
if (parray == NULL){ // array has not been initialized
MessageBox("NULL");
return;
}
if ((parray)->cDims != 1) {// check number of dimensions
 MessageBox("Dim <> 1");
TRACE("%d
",parray->cDims);
return ;
}
TRACE("%d
",parray->cDims);
// get the upper and lower bounds of the array
if (FAILED(SafeArrayGetLBound(parray, 1, &lLb)) ||
	FAILED(SafeArrayGetUBound(parray, 1, &lUb))){
 MessageBox("Array Bound Failed");
return ;
}
TRACE(" %d %d
",lLb,lUb);
// loop through the array and put the elements into array lResult
int i=0;
for (l = lLb; l <= lUb; l++) { 
	if (FAILED(SafeArrayGetElement(parray, &l, &sElem))){
MessageBox("Element failed");
return ; }
TRACE("%d 
",sElem);
lResult[i++] = sElem;
} 
 ///// You can display array in message box
///// To display
 CString s;
 s.Format("%d %d %d .....  %d", lResult[0],lResult[1],..........,lResult[lUb]);
Messagebox(s);
///////////// delete CDialog::OnOk()
}
/////////////////
    2.7 Now in your dialog class OnClose or OnCancel function copy following  
       ashu.DetachDispatch();
	  ashu.ReleaseDispatch();     
    2.8 build your program and run. you may add  header file in your      _Class1.h file, if any problem in building.
 

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