Iterate through rows of dataset in report's custom code

Hello,

How can I iterate through the rows of a dataset in the custom code?
I have a report containing a dataset. I pass the dataset as a parameter to the custom code function. But what then? Where is a reference about the available members etc.?
Here is my dummy sample code so far:

Public Function ShowParameterValues(ByVal ds as DataSet) as object()
  Dim codes() As Object
  Array.Resize(codes,dc.???.Count)
  codes(0)=ds??(field???)(row??)
  return codes
End Function

As the task I want to accomplish is very simple, I want to keep it in the custom code instead of writing any custom assemblies etc.

Thank you!