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copied!<blockquote> <p>I'm now developing a few "sister" components which will share a great deal of the existing component's non-visual functionality and properties. It makes sense, then, to move a lot of that to a parent/superclass which both the new and the old components can then inherit from.</p> <p>What is the best way to "refactor" TFrame inheritance in this way?</p> </blockquote> <p>The crux of your text above perhaps is "component's <strong>non-visual</strong> functionality". So, in this case, IMHO it's best to separate the visual and non-visual layers. </p> <p>So, perhaps it's better to use a decorator:</p> <pre><code>TMySharedEngine = class(Whatever) property LinkedFrame: TFrame; property P1; property P2; ... procedure Proc1; procedure Proc2; ... //etc. end; </code></pre> <p>and in your 'sister' frames to use instances of it:</p> <pre><code>var TMyFrame1 = class(TFrame) ... FDecorator: TMySharedEngine; ... public property MySharedPart: TMySharedEngine read FDecorator; constructor Create(AOwner: TComponent); override; ... end; constructor TMyFrame1.(AOwner: TComponent); override; begin inherited; FDecorator:=TMySharedEngine.Create; //ok, ok do not forget to Free it .Destroy FDecorator.LinkedFrame:=Self; ... end; </code></pre> <p>OTOH, if you want to use your approach you can use Visual Form Inheritance (as Darian suggested) or (more flexible) you can do it by hand: Create, using the IDE the following frames: TBaseFrame, TChildFrame1, TChildFrame2 ... etc. Now go on TChildFrame1's unit and change by hand it's class definition from TChildFrame1 = class(TFrame) to TChildFrame1 = class(TBaseFrame). Compile. It should work. It's recommended though that when you'll do this trick TBaseFrame to be empty in order to avoid possible small quirks (feature collisions etc.)</p> <p>HTH.</p>

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