Delphi OleVariant for string array from COM library

Question

I have a Delphi 2006 client application. This client receives Olevariant type data from the COM server. Function:

procedure OnLimitsChanged(var SymbolsChanged: {??PSafeArray}OleVariant);

This function returns an array of strings. I can not read data like OleVariant from delphi.

From Excel VBA, it works:

Private Sub g_Realtime_OnLimitsChanged(SymbolsChanged() As String)
    Dim i%
    Dim Salir As Boolean
    If UBound(SymbolsChanged) <> -1 Then
        i = 0: Salir = False
        While Not Salir
            If SymbolsChanged(i) = Simbolo Then
                LlamarALimites
                Salir = True
            Else
                i = i + 1
                If i > UBound(SymbolsChanged) Then Salir = True
            End If
        Wend
    End If
End Sub

I tried converting OleVariant to Psafearray ...

procedure TfmConfiguracion.RecibirNuevosTicks(ASender: TObject;
  var ArrayTicks : Olevariant);    
var 
  Data : pSafeArray;
  i,iLow, iHigh : Integer;  
  value : wideString;
begin
  Data:=PSafeArray(TVarData(ArrayTicks).VArray);
  SafeArrayGetLBound(Data,1,iLow);
  SafeArrayGetUBound(Data,1,iHigh);
  for i:=iLow to iHigh do
  begin
    SafeArrayGetElement(Data,i,Value);
    Showmessage(Value);
  end; 

But I only get on this line:

 SafeArrayGetLBound(Data,1,iLow);

Debugger failure notification
Project ... with an error with the message: "Access violation on 0x751de18c: reading address 0xabababab". Cork process. Use the "Step" or "Run" button to continue.

Any advice and suggestions are welcome.

Answer 1

RTL VarArrayAsPSafeArray() PSafeArray (Ole)Variant:

procedure TfmConfiguracion.RecibirNuevosTicks(ASender: TObject; var ArrayTicks : OleVariant);    
var 
  Data : PVarArray; // RTL version of PSafeArray
  //...
begin
  Data := VarArrayAsPSafeArray(ArrayTicks);
  //...
end; 

(Ole)Variant , . VarIsArray(), :

procedure TfmConfiguracion.RecibirNuevosTicks(ASender: TObject; var ArrayTicks : OleVariant);    
var 
  Data : PVarArray;
  //...
begin
  if not VarIsArray(ArrayTicks) then Exit;
  Data := VarArrayAsPSafeArray(ArrayTicks);
  //...
end; 

(Ole)Variant PSafeArray, PSafeArray ( , PSafeArray , ):

procedure TfmConfiguracion.RecibirNuevosTicks(ASender: TObject; var ArrayTicks : Olevariant);    
var 
  i : Integer;  
  value : String;
begin
  if not VarIsArray(ArrayTicks) then Exit;
  for i := VarArrayLowBound(ArrayTicks, 1) to VarArrayHighBound(ArrayTicks, 1) do
  begin
    Value := ArrayTicks[i];
    ShowMessage(Value);
  end; 

Answer 2

RTL , Varant SAFEARRAY:

function VarArrayAsPSafeArray(const V: Variant): PSafeArray;

, .

-

Delphi a Variant . TVarData (

; PSafeArray, Delphi Variant, .

assemblies: PSafeArray;

assemblies := DefaultAppDomain.GetAssemblies;

SAFEARRAY?

function PSafeArrayToVariant(psa: PSafeArray): OleVariant;
begin
   TVarData(v).VType = (VT_ARRAY or VT_xxxx); 
   TVarData(v).VArray := PVarArray(psa);
end;

, , SafeArray; VT_xxxx .

, SAFEARRAY , VType :

fFeatures: Word; FADF_BSTR: BSTR (VT_BSTR) FADF_UNKNOWN. IUnknown (VT_UNKNOWN) FADF_DISPATCH. IDispatch (VT_DISPATCH) FADF_VARIANT. (VT_VARIANT) FADF_HAVEVARTYPE. , SafeArrayGetVartype

function SafeArrayGetVartype(psa: PSafeArray): TVarType; safecall; external 'OleAut32.dll';

function PSafeArrayToVariant(psa: PSafeArray): OleVariant;
var
    features: Word;
    vt: TVarType;
const
    FADF_HAVEVARTYPE = $80;
begin
    features := psa^.fFeatures;
    if (features and FADF_UNKNOWN) = FADF_UNKNOWN then
        vt := VT_UNKNOWN
    else if (features and FADF_DISPATCH) = FADF_DISPATCH then
        vt := VT_DISPATCH
    else if (features and FADF_VARIANT) = FADF_VARIANT then
        vt := VT_VARIANT
    else if (features and FADF_BSTR) <> 0 then
        vt := VT_BSTR
    else if (features and FADF_HAVEVARTYPE) <> 0 then
        vt := SafeArrayGetVartype(psa)
    else
        vt := VT_UI4; //assume 4 bytes of *something*

    TVarData(Result).VType := VT_ARRAY or vt;
    TVarData(Result).VArray := PVarArray(psa);
end;