I am working on a COM Object library with function that returns a VARIANT
with a SAFEARRAY
of BSTR
s. How can I display the values from this VARIANT
instance and save it inside a TStringList
? I tried searching the net with no clear answer.
I tried the following with no success:
Variant V;
String mystr;
VarClear(V);
TVarData(V).VType = varOleStr;
V = ComFunction->GetValues(); //<<<<----- V is empty
mystr = (wchar_t *)(TVarData(V).VString);
Memo1->Lines->Add(mystr);
VarClear(V);
You can use TWideStringDynArray
and let Delphi do the conversion:
procedure LoadStringsFromVariant(const Values: TWideStringDynArray; Strings: TStrings);
var
I: Integer;
begin
Strings.BeginUpdate;
try
for I := Low(Values) to High(Values) do
Strings.Add(Values[I]);
finally
Strings.EndUpdate;
end;
end;
When you call this with your Variant safearray of BSTRs it will be converted to TWideStringDynArray
automatically. An incompatible Variant will cause the runtime error EVariantInvalidArgError
.
To check if a Variant holds a safe array of BSTR you can do this:
IsOK := VarIsArray(V) and (VarArrayDimCount(V) = 1) and (VarType(V) and varTypeMask = varOleStr);
uses ActiveX;
var
VSafeArray: PSafeArray;
LBound, UBound, I: LongInt;
W: WideString;
begin
VSafeArray := ComFunction.GetValues();
SafeArrayGetLBound(VSafeArray, 1, LBound);
SafeArrayGetUBound(VSafeArray, 1, UBound);
for I := LBound to UBound do
begin
SafeArrayGetElement(VSafeArray, I, W);
Memo1.Lines.Add(W);
end;
SafeArrayDestroy(VSafeArray); // cleanup PSafeArray
if you are creating ComFunction
via late binding (CreateOleObject
) you should use:
var
v: Variant;
v := ComFunction.GetValues;
for i := VarArrayLowBound(v, 1) to VarArrayHighBound(v, 1) do
begin
W := VarArrayGet(v, [i]);
Memo1.Lines.Add (W);
end;
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