RE: How do I make my object "browsable"

Hi Axel & Christian,

Thanks a lot for your quick replies.

I had hoped that this would be a bit simpler. It seems rather cumbersome to have to explicitly wrap each data member in a TParameter. Nonetheless, it seems to work. I can now see the data members in the TBrowser.

One more question: How can I get ROOT to either:

 draw the value of the data member in a histogram

or

 write out the value to the command line.

I would like on of these actions to be performed when clicking on the entry in the browser.

Cheers,

    Tobi

-----Original Message-----
From: Christian Holm Christensen [mailto:cholm_at_nbi.dk] Sent: Tue 3/25/2008 12:11
To: Axel Naumann
Cc: Tobias Raufer; roottalk_at_cern.ch
Subject: Re: [ROOT] How do I make my object "browsable"  

Hi Toby,

On Tue, 2008-03-25 at 12:13 +0100, Axel Naumann wrote:
> Hi Tobias,
>
> you'll need to re-implement Browse(TBrowser* b). Check e.g. TBranch's version
> which shows a basic example:
> <http://root.cern.ch/root/html/src/TBranch.cxx.html#pV16>

The problem is your int's and double's - they need to be wrapped in an object of a class for which there's a corresponding TClass instance in the ROOT database. Since

	Root> TClass* int_class = gROOT->GetClass("int");
	Root> TClass* double_class = gROOT->GetClass("double");

both returns null pointers, you can add these members directly - perhaps TBrowser should have the member function

	template <typename T>
	void TBrowser::Add(const char* name, const T& v);

for these kind of things.

Anyway, you need, as mentioned, to wrap your int's and double's e.g.,

        class MyClass : public TObject
        {
        public:
          virtual MyClass() { 
            fArray.Delete();
            if (fDoubleWrap) delete fDoubleWrap;
            if (fIntWrap)    delete fIntWrap;
          }
          MyClass() : fArray(0), fDoubleWrap(0), fIntWrap(0) {}
          Bool_t IsFolder() const { return kTRUE; }
          void Browse(TBrowser* b) {
             b->Add(&fArray);
             if (!fDoubleWrap) fDoubleWrap = new TParameter<double>("fDouble", fDouble);
             if (!fIntWrap)    fIntWrap    = new TParameter<int>("fInt", fInt);
             b->Add(fDoubleWrap);
             b->Add(fIntWrap);
          }
        protected:
           int                fInt;
           double             fDouble;
           TClonesArray       fArray;
           TParameter<double> fDoubleWrap; //! Transient
           TParameter<int>    fIntWrap;    //! Transient
        };
        

yours,

-- 
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