Go Up to Error and Warning Messages (Delphi)
If a data type cannot be converted by the compiler into a Variant, then it is not allowed in an OLE automation call.
program Produce;
type
Base = class
xย : Integer;
end;
var
Bย : Base;
Vย : Variant;
begin
V.Dispatch(B);
end.
A class cannot be converted into a Variant type, so it is not allowed in an OLE call.
program Solve;
type
Base = class
xย : Integer;
end;
var
Bย : Base;
Vย : Variant;
begin
V.Dispatch(B.i);
end.
The only solution to this problem is to manually convert these data types to Variants or to only use data types that can automatically be converted into a Variant.