How to execute a method by name

Problem/Question/Abstract:

I have a reference to a TMethod (with its Data and Code pointers) and would like to execute the associated method. Does anyone know how I can do this?

Answer:

Here is an example that executes a method by name. Note that the method to be called (in the example that is SomeMethod) must be declared as published, otherwise MethodAddress wil return nil.


{ ... }
type
  PYourMethod = ^TYourMethod;
  TYourMethod = procedure(S: string) of object;

procedure TMainForm.Button1Click(Sender: TObject);
begin
  ExecMethodByName('SomeMethod');
end;

procedure TMainForm.ExecMethodByName(AName: string);
var
  PAddr: PYourMethod;
  M: TMethod;
begin
  PAddr := MethodAddress(AName);
  if PAddr <> nil then
  begin
    M.Code := PAddr;
    M.Data := Self;
    TYourMethod(M)('hello');
  end;
end;

procedure TMainForm.SomeMethod(S: string);
begin
  ShowMessage(S);
end;