Re: I met with difficulty for building a VLE Extension.

[Robert Halstead]

Yong-Woong Kim wrote: Hi, gurus!   I met with difficulty for building a VLE Extension.   My goal is to build a VLE Extension, to which users can take a class as its child.   First, I programmed the next class;   ||---------------------------------------------------------------------------- || /comp/PKG.BASEFORM/FRAMEWORK.BASEFORM.scurl ||---------------------------------------------------------------------------- {define-class public TBaseForm {inherits Dialog}     field protected fr : Frame = {Frame width={make-elastic}, height={make-elastic}}     {constructor public {default label:any="TBaseForm", ...}         {construct-super                border-width=1px, border-color="black", border-style="flat",         ...     }         {self.add replace?=true,         {VBox width={make-elastic}, height={make-elastic}, background="",             {CommandButton label=label},             self.fr         }     }   }     {method public {add-child g:any}:void     {self.fr.add replace?=true, g}   } } ||----------------------------------------------------------------------------   As you already noticed it from the source code, if users take a class as its child, the class becomes a child of TBaseForm.fr : Frame.   Next, I successfully built TBaseForm to a VLE extension, so when I launched the VLE, I can see its icon in the palettes and use it, too.   However, when I ran it after I took a RecordGrid on it by a drag and drop, an error raised; "A TBaseForm may Contain only a single graphic child."   Before I ran it, I certainly saw that the RecordGrid was added as a child of TBaseForm in the Layout tree.   I think the problem is that the TBaseForm constructor already adds a child (the CommandButton) to the TBaseForm object.  So then when the code generated by the VLE tries to add your RecordGrid object as a child of the TBaseForm, an error occurs because the TBaseForm already has a child object. Why does the TBaseForm constructor add this CommandButton as a child of the TBaseForm object? -Bert