Question

I try to do list of procedures this way:

type

TProc = procedure of object;

TMyClass=class
private
fList:Tlist;
function getItem(index:integer):TProc;
{....}
public
{....}
end;
implementation
{....}
function TMyClass.getItem(index: Integer): TProc;
begin
 Result:= TProc(flist[index]);// <--- error is here!
end;
{....}
end.

and get error:

E2089 Invalid typecast

How can I fix it?
As I see, I can make a fake class with only one property Proc:TProc; and make list of it. But I feel that it’s a bad way, isn’t it?

PS: project have to be delphi-7-compatible.

Answer 1

The typecast is invalid because you can not fit a method pointer to a pointer, a method pointer is in fact two pointers first being the address of the method and the second being a reference to the object that the method belongs. See Procedural Types in the documentation. This will not work in any version of Delphi.