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COleSafeArray Class

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A class for working with arrays of arbitrary type and dimension.

Syntax

class COleSafeArray : public tagVARIANT

Members

Public Constructors

Name Description
COleSafeArray::COleSafeArray Constructs a COleSafeArray object.

Public Methods

Name Description
COleSafeArray::AccessData Retrieves a pointer to the array data.
COleSafeArray::AllocData Allocates memory for the array.
COleSafeArray::AllocDescriptor Allocates memory for the safe array descriptor.
COleSafeArray::Attach Gives control of the existing VARIANT array to the COleSafeArray object.
COleSafeArray::Clear Frees all data in the underlying VARIANT.
COleSafeArray::Copy Creates a copy of an existing array.
COleSafeArray::Create Creates a safe array.
COleSafeArray::CreateOneDim Creates a one-dimensional COleSafeArray object.
COleSafeArray::Destroy Destroys an existing array.
COleSafeArray::DestroyData Destroys data in a safe array.
COleSafeArray::DestroyDescriptor Destroys a descriptor of a safe array.
COleSafeArray::Detach Detaches the VARIANT array from the COleSafeArray object (so that the data will not be freed).
COleSafeArray::GetByteArray Copies the contents of the safe array into a CByteArray.
COleSafeArray::GetDim Returns the number of dimensions in the array.
COleSafeArray::GetElement Retrieves a single element of the safe array.
COleSafeArray::GetElemSize Returns the size, in bytes, of one element in a safe array.
COleSafeArray::GetLBound Returns the lower bound for any dimension of a safe array.
COleSafeArray::GetOneDimSize Returns the number of elements in the one-dimensional COleSafeArray object.
COleSafeArray::GetUBound Returns the upper bound for any dimension of a safe array.
COleSafeArray::Lock Increments the lock count of an array and places a pointer to the array data in the array descriptor.
COleSafeArray::PtrOfIndex Returns a pointer to the indexed element.
COleSafeArray::PutElement Assigns a single element into the array.
COleSafeArray::Redim Changes the least significant (rightmost) bound of a safe array.
COleSafeArray::ResizeOneDim Changes the number of elements in a one-dimensional COleSafeArray object.
COleSafeArray::UnaccessData Decrements the lock count of an array and invalidates the pointer retrieved by AccessData.
COleSafeArray::Unlock Decrements the lock count of an array so it can be freed or resized.

Public Operators

Name Description
COleSafeArray::operator LPCVARIANT Accesses the underlying VARIANT structure of the COleSafeArray object.
COleSafeArray::operator LPVARIANT Accesses the underlying VARIANT structure of the COleSafeArray object.
COleSafeArray::operator = Copies values into a COleSafeArray object ( SAFEARRAY, VARIANT, COleVariant, or COleSafeArray array).
COleSafeArray::operator == Compares two variant arrays ( SAFEARRAY, VARIANT, COleVariant, or COleSafeArray arrays).
COleSafeArray::operator << Outputs the contents of a COleSafeArray object to the dump context.

Remarks

COleSafeArray derives from the OLE VARIANT structure. The OLE SAFEARRAY member functions are available through COleSafeArray, as well as a set of member functions specifically designed for one-dimensional arrays of bytes.

Inheritance Hierarchy

tagVARIANT

COleSafeArray

Requirements

Header: afxdisp.h

COleSafeArray::AccessData

Retrieves a pointer to the array data.

void AccessData(void** ppvData);

Parameters

ppvData
A pointer to a pointer to the array data.

Remarks

On error, the function throws a CMemoryException or COleException.

Example

void CMainFrame::Sort(VARIANT* vArray)
{
   COleSafeArray sa;
   BSTR *pbstr;
   TCHAR buf[1024];
   LONG cElements, lLBound, lUBound;
  
   //needed for OLE2T macro below, include afxpriv.h
   USES_CONVERSION;

   // Type check VARIANT parameter. It should contain a BSTR array
   // passed by reference. The array must be passed by reference it is
   // an in-out-parameter.
   if (V_VT(vArray) != (VT_ARRAY | VT_BSTR))
   {
      AfxThrowOleDispatchException(1001, 
         _T("Type Mismatch in Parameter. Pass a string array by reference"));
   }

   // clears data in sa and copies the variant data into sa
   sa.Attach(*vArray);

   // Check that array is 1 dimensional
   if (sa.GetDim() != 1)
   {
      AfxThrowOleDispatchException(1002, 
         _T("Type Mismatch in Parameter. Pass a one-dimensional array"));
   }

   try 
   {
      // Get array bounds.
      sa.GetLBound(1, &lLBound);
      sa.GetUBound(1, &lUBound);

      // Get a pointer to the elements of the array
      // and increments the lock count on the array
      sa.AccessData((LPVOID*)&pbstr);

      //get no. of elements in array
      cElements = lUBound - lLBound + 1;
      for (int i = 0; i < cElements; i++)
      {
         //output the elements of the array
         _stprintf_s(buf, 1024, _T("[%s]\n"), OLE2T(pbstr[i]));
         OutputDebugString(buf);
      }
      
      //decrement lock count
      sa.UnaccessData();
   }
   catch (COleException *pEx)
   {
      AfxThrowOleDispatchException(1003, 
         _T("Unexpected Failure in FastSort method"));
      pEx->Delete();
   }
}

COleSafeArray::AllocData

Allocates memory for a safe array.

void AllocData();

Remarks

On error, the function throws a CMemoryException or COleException.

COleSafeArray::AllocDescriptor

Allocates memory for the descriptor of a safe array.

void AllocDescriptor(DWORD dwDims);

Parameters

dwDims
Number of dimensions in the safe array.

Remarks

On error, the function throws a CMemoryException or COleException.

COleSafeArray::Attach

Gives control of the data in an existing VARIANT array to the COleSafeArray object.

void Attach(VARIANT& varSrc);

Parameters

varSrc
A VARIANT object. The varSrc parameter must have the VARTYPEVT_ARRAY.

Remarks

The source VARIANT's type is set to VT_EMPTY. This function clears the current array data, if any.

Example

See the example for COleSafeArray::AccessData.

COleSafeArray::Clear

Clears the safe array.

void Clear();

Remarks

The function clears a safe array by setting the VARTYPE of the object to VT_EMPTY. The current contents are released and the array is freed.

COleSafeArray::COleSafeArray

Constructs a COleSafeArray object.

COleSafeArray();

 
COleSafeArray(
    const SAFEARRAY& saSrc,
    VARTYPE vtSrc);

 
COleSafeArray(
    LPCSAFEARRAY pSrc,
    VARTYPE vtSrc);  
  
COleSafeArray(const COleSafeArray& saSrc);  
COleSafeArray(const VARIANT& varSrc);  
  COleSafeArray(LPCVARIANT pSrc);  
COleSafeArray(const COleVariant& varSrc);
```  
  
### Parameters  
 `saSrc`  
 An existing `COleSafeArray` object or **SAFEARRAY** to be copied into the new `COleSafeArray` object.  
  
 `vtSrc`  
 The **VARTYPE** of the new `COleSafeArray` object.  
  
 `psaSrc`  
 A pointer to a **SAFEARRAY** to be copied into the new `COleSafeArray` object.  
  
 *varSrc*  
 An existing **VARIANT** or `COleVariant` object to be copied into the new `COleSafeArray` object.  
  
 `pSrc`  
 A pointer to a **VARIANT** object to be copied into the new `COleSafeArray` object.  
  
### Remarks  
 All of these constructors create new `COleSafeArray` objects. If there is no parameter, an empty `COleSafeArray` object is created ( `VT_EMPTY`). If the `COleSafeArray` is copied from another array whose [VARTYPE](assetId:///317b911b-1805-402d-a9cb-159546bc88b4) is known implicitly (a `COleSafeArray`, `COleVariant`, or **VARIANT**), the **VARTYPE** of the source array is retained and need not be specified. If the `COleSafeArray` is copied from another array whose **VARTYPE** is not known ( **SAFEARRAY**), the **VARTYPE** must be specified in the `vtSrc` parameter.  
  
 On error, the function throws a [CMemoryException](../Topic/CMemoryException%20Class.md) or [COleException](../Topic/COleException%20Class.md).  
  
##  <a name="colesafearray__copy"></a>  COleSafeArray::Copy  
 Creates a copy of an existing safe array.

void Copy(LPSAFEARRAY* ppsa);

  
### Parameters  
 *ppsa*  
 Pointer to a location in which to return the new array descriptor.  
  
### Remarks  
 On error, the function throws a [CMemoryException](../Topic/CMemoryException%20Class.md) or [COleException](../Topic/COleException%20Class.md).  
  
##  <a name="colesafearray__create"></a>  COleSafeArray::Create  
 Allocates and initializes the data for the array.

void Create( VARTYPE vtSrc,
DWORD dwDims,
DWORD* rgElements);

void Create( VARTYPE vtSrc,
DWORD dwDims,
SAFEARRAYBOUND* rgsabounds);

  
### Parameters  
 `vtSrc`  
 The base type of the array (that is, the **VARTYPE** of each element of the array). The **VARTYPE** is restricted to a subset of the variant types. Neither the **VT_ARRAY** nor the **VT_BYREF** flag can be set. `VT_EMPTY` and **VT_NULL** are not valid base types for the array. All other types are legal.  
  
 `dwDims`  
 Number of dimensions in the array. This can be changed after the array is created with [Redim](#colesafearray__redim).  
  
 *rgElements*  
 Pointer to an array of the number of elements for each dimension in the array.  
  
 *rgsabounds*  
 Pointer to a vector of bounds (one for each dimension) to allocate for the array.  
  
### Remarks  
 This function will clear the current array data if necessary. On error, the function throws a [CMemoryException](../Topic/CMemoryException%20Class.md).  
  
### Example  
 [!CODE [NVC_MFCOleContainer#27](../CodeSnippet/VS_Snippets_Cpp/NVC_MFCOleContainer#27)]  
  
##  <a name="colesafearray__createonedim"></a>  COleSafeArray::CreateOneDim  
 Creates a new one-dimensional `COleSafeArray` object.

void CreateOneDim( VARTYPE vtSrc,
DWORD dwElements,
const void* pvSrcData = NULL,
long nLBound = 0);

  
### Parameters  
 `vtSrc`  
 The base type of the array (that is, the **VARTYPE** of each element of the array).  
  
 `dwElements`  
 Number of elements in the array. This can be changed after the array is created with [ResizeOneDim](#colesafearray__resizeonedim).  
  
 `pvSrcData`  
 Pointer to the data to copy into the array.  
  
 *nLBound*  
 The lower bound of the array.  
  
### Remarks  
 The function allocates and initializes the data for the array, copying the specified data if the pointer `pvSrcData` is not **NULL**.  
  
 On error, the function throws a [CMemoryException](../Topic/CMemoryException%20Class.md).  
  
### Example  
 [!CODE [NVC_MFCOleContainer#28](../CodeSnippet/VS_Snippets_Cpp/NVC_MFCOleContainer#28)]  
  
##  <a name="colesafearray__destroy"></a>  COleSafeArray::Destroy  
 Destroys an existing array descriptor and all the data in the array.

void Destroy();

  
### Remarks  
 If objects are stored in the array, each object is released. On error, the function throws a [CMemoryException](../Topic/CMemoryException%20Class.md) or [COleException](../Topic/COleException%20Class.md).  
  
##  <a name="colesafearray__destroydata"></a>  COleSafeArray::DestroyData  
 Destroys all the data in a safe array.

void DestroyData();

  
### Remarks  
 If objects are stored in the array, each object is released. On error, the function throws a [CMemoryException](../Topic/CMemoryException%20Class.md) or [COleException](../Topic/COleException%20Class.md).  
  
##  <a name="colesafearray__destroydescriptor"></a>  COleSafeArray::DestroyDescriptor  
 Destroys a descriptor of a safe array.

void DestroyDescriptor();

  
### Remarks  
 On error, the function throws a [CMemoryException](../Topic/CMemoryException%20Class.md) or [COleException](../Topic/COleException%20Class.md).  
  
##  <a name="colesafearray__detach"></a>  COleSafeArray::Detach  
 Detaches the **VARIANT** data from the `COleSafeArray` object.

VARIANT Detach();

  
### Return Value  
 The underlying **VARIANT** value in the `COleSafeArray` object.  
  
### Remarks  
 The function detaches the data in a safe array by setting the [VARTYPE](assetId:///317b911b-1805-402d-a9cb-159546bc88b4) of the object to `VT_EMPTY`. It is the caller's responsibility to free the array by calling the Windows function [VariantClear](assetId:///28741d81-8404-4f85-95d3-5c209ec13835).  
  
 On error, the function throws a [COleException](../Topic/COleException%20Class.md).  
  
### Example  
  See the example for [COleSafeArray::PutElement](#colesafearray__putelement).  
  
##  <a name="colesafearray__getbytearray"></a>  COleSafeArray::GetByteArray  
 Copies the contents of the safe array into a `CByteArray`.

void GetByteArray(CByteArray& bytes);

  
### Parameters  
 `bytes`  
 A reference to a [CByteArray](../Topic/CByteArray%20Class.md) object.  
  
##  <a name="colesafearray__getdim"></a>  COleSafeArray::GetDim  
 Returns the number of dimensions in the `COleSafeArray` object.

DWORD GetDim();

  
### Return Value  
 The number of dimensions in the safe array.  
  
### Example  
 [!CODE [NVC_MFCOleContainer#27](../CodeSnippet/VS_Snippets_Cpp/NVC_MFCOleContainer#27)]  
  
##  <a name="colesafearray__getelement"></a>  COleSafeArray::GetElement  
 Retrieves a single element of the safe array.

void GetElement( long* rgIndices,
void* pvData);

  
### Parameters  
 `rgIndices`  
 Pointer to an array of indexes for each dimension of the array.  
  
 `pvData`  
 Pointer to the location to place the element of the array.  
  
### Remarks  
 This function automatically calls the windows functions `SafeArrayLock` and `SafeArrayUnlock` before and after retrieving the element. If the data element is a string, object, or variant, the function copies the element in the correct way. The parameter `pvData` should point to a large enough buffer to contain the element.  
  
 On error, the function throws a [CMemoryException](../Topic/CMemoryException%20Class.md) or [COleException](../Topic/COleException%20Class.md).  
  
### Example  
 [!CODE [NVC_MFCOleContainer#29](../CodeSnippet/VS_Snippets_Cpp/NVC_MFCOleContainer#29)]  
  
##  <a name="colesafearray__getelemsize"></a>  COleSafeArray::GetElemSize  
 Retrieves the size of an element in a `COleSafeArray` object.

DWORD GetElemSize();

  
### Return Value  
 The size, in bytes, of the elements of a safe array.  
  
##  <a name="colesafearray__getlbound"></a>  COleSafeArray::GetLBound  
 Returns the lower bound for any dimension of a `COleSafeArray` object.

void GetLBound( DWORD dwDim,
long* pLBound);

  
### Parameters  
 `dwDim`  
 The array dimension for which to get the lower bound.  
  
 *pLBound*  
 Pointer to the location to return the lower bound.  
  
### Remarks  
 On error, the function throws a [COleException](../Topic/COleException%20Class.md).  
  
### Example  
 [!CODE [NVC_MFCOleContainer#30](../CodeSnippet/VS_Snippets_Cpp/NVC_MFCOleContainer#30)]  
  
##  <a name="colesafearray__getonedimsize"></a>  COleSafeArray::GetOneDimSize  
 Returns the number of elements in the one-dimensional `COleSafeArray` object.

DWORD GetOneDimSize();

  
### Return Value  
 The number of elements in the one-dimensional safe array.  
  
### Example  
  See the example for [COleSafeArray::CreateOneDim](#colesafearray__createonedim).  
  
##  <a name="colesafearray__getubound"></a>  COleSafeArray::GetUBound  
 Returns the upper bound for any dimension of a safe array.

void GetUBound( DWORD dwDim,
long* pUBound);

  
### Parameters  
 `dwDim`  
 The array dimension for which to get the upper bound.  
  
 *pUBound*  
 Pointer to the location to return the upper bound.  
  
### Remarks  
 On error, the function throws a [COleException](../Topic/COleException%20Class.md).  
  
### Example  
 [!CODE [NVC_MFCOleContainer#31](../CodeSnippet/VS_Snippets_Cpp/NVC_MFCOleContainer#31)]  
  
##  <a name="colesafearray__lock"></a>  COleSafeArray::Lock  
 Increments the lock count of an array and place a pointer to the array data in the array descriptor.

void Lock();

  
### Remarks  
 On error, it throws a [COleException](../Topic/COleException%20Class.md).  
  
 The pointer in the array descriptor is valid until `Unlock` is called. Calls to `Lock` can be nested; an equal number of calls to `Unlock` are required.  
  
 An array cannot be deleted while it is locked.  
  
##  <a name="colesafearray__operator_lpcvariant"></a>  COleSafeArray::operator LPCVARIANT  
 Call this casting operator to access the underlying **VARIANT** structure for this `COleSafeArray` object.

operator LPCVARIANT() const;

  
##  <a name="colesafearray__operator_lpvariant"></a>  COleSafeArray::operator LPVARIANT  
 Call this casting operator to access the underlying **VARIANT** structure for this `COleSafeArray` object.

operator LPVARIANT();

  
### Remarks  
 Note that changing the value in the **VARIANT** structure accessed by the pointer returned by this function will change the value of this `COleSafeArray` object.  
  
##  <a name="colesafearray__operator__eq"></a>  COleSafeArray::operator =  
 These overloaded assignment operators copy the source value into this `COleSafeArray` object.

COleSafeArray& operator=(const COleSafeArray& saSrc);
COleSafeArray& operator=(const VARIANT& varSrc);
COleSafeArray& operator=(LPCVARIANT pSrc);
COleSafeArray& operator=(const COleVariant& varSrc); ```

Remarks

A brief description of each operator follows:

  • operator =( saSrc ) Copies an existing COleSafeArray object into this object.

  • operator =( varSrc**)** Copies an existing VARIANT or COleVariant array into this object.

  • operator =( pSrc ) Copies the VARIANT array object accessed by pSrc into this object.

COleSafeArray::operator ==

This operator compares two arrays ( SAFEARRAY, VARIANT, COleVariant, or COleSafeArray arrays) and returns nonzero if they are equal; otherwise 0.

BOOL operator==(const SAFEARRAY& saSrc) const;  BOOL operator==(LPCSAFEARRAY pSrc) const;  
   
BOOL operator==(const COleSafeArray& saSrc) const;  BOOL operator==(const VARIANT& varSrc) const;  
   
BOOL operator==(LPCVARIANT pSrc) const;  BOOL operator==(const COleVariant& varSrc) const;  ```  
  
### Remarks  
 Two arrays are equal if they have an equal number of dimensions, equal size in each dimension, and equal element values.  
  
##  <a name="colesafearray__operator__lt__lt_"></a>  COleSafeArray::operator &lt;&lt;  
 The `COleSafeArray` insertion (<<) operator supports diagnostic dumping and storing of a `COleSafeArray` object to an archive.

CDumpContext& AFXAPI operator<<( CDumpContext& dc,
COleSafeArray& saSrc);

  
##  <a name="colesafearray__ptrofindex"></a>  COleSafeArray::PtrOfIndex  
 Returns a pointer to the element specified by the index values.

void PtrOfIndex( long* rgIndices,
void** ppvData);

  
### Parameters  
 `rgIndices`  
 An array of index values that identify an element of the array. All indexes for the element must be specified.  
  
 `ppvData`  
 On return, pointer to the element identified by the values in `rgIndices`.  
  
##  <a name="colesafearray__putelement"></a>  COleSafeArray::PutElement  
 Assigns a single element into the array.

void PutElement( long* rgIndices,
void* pvData);

  
### Parameters  
 `rgIndices`  
 Pointer to an array of indexes for each dimension of the array.  
  
 `pvData`  
 Pointer to the data to assign to the array. **VT_DISPATCH**, **VT_UNKNOWN**, and `VT_BSTR` variant types are pointers and do not require another level of indirection.  
  
### Remarks  
 This function automatically calls the Windows functions [SafeArrayLock](https://msdn.microsoft.com/library/windows/desktop/ms221492.aspx) and [SafeArrayUnlock](https://msdn.microsoft.com/library/windows/desktop/ms221246.aspx) before and after assigning the element. If the data element is a string, object, or variant, the function copies it correctly, and if the existing element is a string, object, or variant, it is cleared correctly.  
  
 Note that you can have multiple locks on an array, so you can put elements into an array while the array is locked by other operations.  
  
 On error, the function throws a [CMemoryException](../Topic/CMemoryException%20Class.md) or [COleException](../Topic/COleException%20Class.md).  
  
### Example  
 [!CODE [NVC_MFCOleContainer#32](../CodeSnippet/VS_Snippets_Cpp/NVC_MFCOleContainer#32)]  
  
##  <a name="colesafearray__redim"></a>  COleSafeArray::Redim  
 Changes the least significant (rightmost) bound of a safe array.

void Redim(SAFEARRAYBOUND* psaboundNew);

  
### Parameters  
 *psaboundNew*  
 Pointer to a new safe array bound structure containing the new array bound. Only the least significant dimension of an array may be changed.  
  
### Remarks  
 On error, the function throws a [COleException](../Topic/COleException%20Class.md).  
  
##  <a name="colesafearray__resizeonedim"></a>  COleSafeArray::ResizeOneDim  
 Changes the number of elements in a one-dimensional `COleSafeArray` object.

void ResizeOneDim(DWORD dwElements);

  
### Parameters  
 `dwElements`  
 Number of elements in the one-dimensional safe array.  
  
### Remarks  
 On error, the function throws a [COleException](../Topic/COleException%20Class.md).  
  
### Example  
  See the example for [COleSafeArray::CreateOneDim](#colesafearray__createonedim).  
  
##  <a name="colesafearray__unaccessdata"></a>  COleSafeArray::UnaccessData  
 Decrements the lock count of an array and invalidates the pointer retrieved by `AccessData`.

void UnaccessData();

  
### Remarks  
 On error, the function throws a [COleException](../Topic/COleException%20Class.md).  
  
### Example  
  See the example for [COleSafeArray::AccessData](#colesafearray__accessdata).  
  
##  <a name="colesafearray__unlock"></a>  COleSafeArray::Unlock  
 Decrements the lock count of an array so it can be freed or resized.

void Unlock();

  
### Remarks  
 This function is called after access to the data in an array is finished. On error, it throws a [COleException](../Topic/COleException%20Class.md).  
  
## See Also  
 [Hierarchy Chart](../Topic/Hierarchy%20Chart.md)   
 [COleVariant Class](../Topic/COleVariant%20Class.md)   
 [CRecordset Class](../Topic/CRecordset%20Class.md)   
 [CDatabase Class](../Topic/CDatabase%20Class.md)