CODEWITHSUNDEEP
delphiinheritancevirtual-functions
Jerry Dodge
Jerry Dodge

Reputation: 27276

How can I make "inherited" appear at the end of my procedure instead of beginning?

First of all, I doubt this is even possible, but if it is, I'd love to know how. I recall seeing this behavior before, but it could be explicitly implemented in the IDE.

I have a base form which I then inherit into various other forms. In the base form, I have a number of virtual methods which are to be overridden and implemented by the inherited forms.

There are certain virtual methods which expect inherited to be called at the end of the procedure. However, by default, it gets automatically inserted at the beginning. This tends to cause confusion, specifically forgetting to call it at the end instead of the beginning.

How could I force inherited to get inserted at the end instead of the beginning, like below, if at all possible?

procedure TMyForm.DoStuff;
begin

  inherited;
end;

Upvotes: 3

Views: 318

Answers (2)

J...
J...

Reputation: 31403

To add to David's answer, if you need to enforce this order of operations the best way to do it is by changing the design. Decoupling the operations which need to happen afterwards can be done something like this :

type
  TMyBase = class
    protected
      DoBeforeSomething : procedure; virtual; abstract;
    public
      DoSomething : procedure;
  end;

  TMyCustom = class(TMyBase)
    protected
      DoBeforeSomething : procedure; override;
  end;

procedure TMyBase.DoSomething;
begin
  DoBeforeSomething;
  // Do common things now...
end;

procedure TMyCustom.DoBeforeSomething;
begin
  inherited;
  // some custom things...
end;

Here the consumer would always call the DoSomething method to perform whatever operation is intended but the inheriting class would override DoBeforeSomething, which is called first in DoSomething before whatever other operations need to be done.

This way the descendent class doesn't have to worry about overriding DoSomething itself and calling inherited in the "wrong" place, the design of the class takes care of getting the operations in the correct order.

Upvotes: 3

David Heffernan
David Heffernan

Reputation: 612993

You can't change this behaviour of the IDE.

The IDE knows that certain methods, e.g. overridden destructors, expect the inherited statement to appear at the end of the method body. For such methods, the IDE does indeed place the call to inherited at the end of the method body when performing class completion. But there is no mechanism for you to tell the IDE that other methods, about which it knows nothing, are to be treated that way.

Upvotes: 6

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