Solved

Creating SAFEARRAY with multiple data types.

Posted on 2000-05-08
4
646 Views
Last Modified: 2011-04-14
I want to create a safe array that contains different types of data. For example, I am trying to create a 2d array with legnth 4. I want all the elements array[0][0], array[0][1], array[0][2], array[0][3], to be BSTRs. I want all the elements array[1][0], array[1][1], array[1][2], array[1][3] to be floats. How can I create this array and set the elements correctly? Please provide sample code.

Here is what I have so far.

  VARIANT ChartData;
  VariantInit( &ChartData );
  ChartData.vt = VT_ARRAY | VT_VARIANT;

  SAFEARRAYBOUND rgb[] = { 4, 0 };
  SAFEARRAY *psa = SafeArrayCreate( VT_VARIANT, 2, rgb );

  if( psa )
  {
    long* data;

    SafeArrayAccessData( psa, ( void ** )&data );

    // SET ARRAY ELEMENTS!!?

    SafeArrayUnaccessData( psa );
  }

  ChartData.parray = psa;
0
Comment
Question by:cdgough
  • 2
4 Comments
 
LVL 1

Expert Comment

by:ntdragon
ID: 2790062
you should build a template class named safearray
something like:

template <class T,int S>
class SafeArray:parent{
   T arr1[S];
public:
SafeArray(){}
T&operator[](int x){
//something like
   return arr1[x];
}
~SafeArray(){}
};

in main to make safearray of BSTRs
and another one for flosts

then to make a container in size two that cont[0] will the first safearray
and cont[1] the second

i hope you got the idea






0
 

Author Comment

by:cdgough
ID: 2790496
This doesn't look right.

I need two different types of variants in the same array. A single array with some BSTRs and some floats.
0
 
LVL 1

Accepted Solution

by:
sharonk earned 100 total points
ID: 2791510
The following C++ code function creates a safearray like the one you requested (with BSTR and floats):

STDMETHODIMP CArrayTest::CreateArray(VARIANT *result)
{
      SAFEARRAY *psa;
      HRESULT hr;
      VARIANT var;            
      SAFEARRAYBOUND rgsabound[2];
      long element[2];
      char sz[256];
      int count;

      rgsabound[0].lLbound = 0;
      rgsabound[0].cElements = 10;
      rgsabound[1].lLbound = 0;
      rgsabound[1].cElements = 10;

      psa = SafeArrayCreate(VT_VARIANT, 2, rgsabound);
      if(psa == NULL)
            return E_FAIL;

      for(count = 0; count < 10; count++)
      {
            // Prepare BSTR value
            sprintf(sz, "Hello%d", count);
            V_BSTR(&var) = SysAllocString(_bstr_t(sz));
            V_VT(&var) = VT_BSTR;
            // Prepare position
            element[0] = 0;
            element[1] = count;
            // Put element
            hr = SafeArrayPutElement(psa, element, &var);                    
            if (!SUCCEEDED(hr))
                  return E_FAIL;
            VariantClear(&var);
                  
            // Prepare float value
            V_R4(&var) = (float)count;
            V_VT(&var) = VT_R4;
            // Prepare position
            element[0] = 1;
            element[1] = count;
            // Put element
            hr = SafeArrayPutElement(psa, element, &var);                    
            if (!SUCCEEDED(hr))
                  return E_FAIL;
            VariantClear(&var);                          
      }
            
      // Copy Results to return Value
      V_VT(result) = VT_ARRAY | VT_VARIANT;
      V_ARRAY(result) = psa;
      
      return S_OK;
}

The following VB code test this function (assuming it resides in an impleemented interface):

    Dim a As New ArrayTest
    x = a.CreateArray
    For i = 0 To 9
        MsgBox x(0, i) & " " & x(1, i)
    Next

0
 

Author Comment

by:cdgough
ID: 2794849
This is exactly what I was looking for. Thanks.
0

Featured Post

Live: Real-Time Solutions, Start Here

Receive instant 1:1 support from technology experts, using our real-time conversation and whiteboard interface. Your first 5 minutes are always free.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

  Included as part of the C++ Standard Template Library (STL) is a collection of generic containers. Each of these containers serves a different purpose and has different pros and cons. It is often difficult to decide which container to use and …
This article will show you some of the more useful Standard Template Library (STL) algorithms through the use of working examples.  You will learn about how these algorithms fit into the STL architecture, how they work with STL containers, and why t…
The viewer will learn additional member functions of the vector class. Specifically, the capacity and swap member functions will be introduced.
The viewer will be introduced to the technique of using vectors in C++. The video will cover how to define a vector, store values in the vector and retrieve data from the values stored in the vector.

775 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question