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Fernanda · Guest

Hi,
Im trying to call a property from my COM DLL made in Delphi into a C#
Application. The detail is that this property is an array of objects. It's
defined in Delphi's type library like:

Attributes - Name: Vetor
- Type: SAFEARRAY(IUnknown)
Parameters - Return Type: HRESULT
- Type: SAFEARRAY(IUnknown)*
- Modifier: [out, retval]

Delphi's function to get this property is described as:

function TAtivos.Get_Vetor(out Value: PSafeArray): HResult;
var
i: Integer;
ArrayBounds: TSafeArrayBound;
ArrayData: Pointer;
begin
ArrayBounds.lLbound := 0;
ArrayBounds.cElements := FArraySize; //............ where FArraySize is
an integer property in class
Value := SafeArrayCreate (varUnknown, 1, ArrayBounds);
if SafeArrayAccessData (Value, ArrayData) = S_OK then begin
for i:=0 to 4 do
Vetor(ArrayData)[i] := FVetAtivo[i]; //....... array inicialized
with the objects which I want to export
SafeArrayUnaccessData (Value);
end;
Result := S_OK;
end;

I tested if Vetor was receiving data in function above and it's ok but I get
an NullReferenceException in C# application when function Get_Vetor tries to
return Value.

Is there any good sould to help me ? ;-)

Fernanda Menks

krisztian pinter · Guest

hey, I did once stuck with safe arrays, and i'm still don't familiar with these animals, but i've found a very wierd solution.

just use a variant array, and then cast it's VArray member to PSafeArray

Value := PSafeArray(TVarData(YourArray).VArray);

i don't have the faintest clue why does it work, but it did for me.

"Fernanda" <fernanda (AT) luz-ef (DOT) com> wrote: