Calling method by name Delphi 10 Firemonkey

Question

I am trying to call methods by name in a firemonkey project. But so far no luck.

Below is my code:

type
  TExecute = procedure of object;
  TUpdates= class(TDataModule)
     procedure UpdateToVersion(Version: Integer);
  private
     procedure UpdateToVersion1;
     procedure UpdateToVersion2;
     procedure UpdateToVersion3;
     procedure Call(Name: string);
  public
  end;

procedure TUpdates.Call(Name: String);
var
  m:TMethod;
  Exe:TExecute;
begin
  m.Data := pointer(Self);
  m.Code := Self.MethodAddress(Name);
  Exe := TExecute(m);
  Exe;
end;

procedure TUpdates.UpdateToVersion(Version: Integer);
begin
   Call('UpdateToVersion'+version.ToString);
end;

procedure TUpdates.UpdateToVersion1;
begin
   //code
end;

procedure TUpdates.UpdateToVersion2;
begin
   //code
end;

procedure TUpdates.UpdateToVersion3;
begin
   //code
end;

Results: When I call for example UpdateToVersion(1) I get an access violation and procedure UpdateToVersion1 doesn't get called.

I got this code from an example from the link below: http://www.swissdelphicenter.ch/torry/showcode.php?id=799

Answer 1

MethodAddress requires that the method is published, as is the method in the example code. Your methods are private. Hence MethodAddress fails and returns nil.

Solve the problem by publishing the methods.

If you wish to perform this sort of task with non-published methods then you will need to use enhanced RTTI.