what does a Object value return?

[C# Programming]

I want retrieve tagelements of a html details using c#.
In the html page, if I get

PC_COLLECTIONRECEIPT_205092

mshtml.HTMLLabelElement labelElem = (mshtml.HTMLLabelElement)htmlElement; // where htmlElement.outerHTML gives above text
labelElem.onclick gives a object value.
From this object variable how can i get the string "openFile('/20095/PC_COLLECTIONRECEIPT_205092.pdf')"