I am currently writing a graph producing application for a client. The
graphs all have to be bar charts. However, I need to put in a horizontal
line on top of the bar chart. the graph control simply won't do this.

(I have also tried creating a line object and placing it over the graph
object, in my desparation to solve this probelm. This looks okay the first
time I do it in design time, but during run time the graph axes'
co-ordinates will change with each different graph, and I can't ascertain
what the new axes' co-ordinates are, therefore my line object suddenly
finds itself in the wrong place! Is there a way to work out what the axes
co-ordinates are?)

I was hoping someone might know C++ and could recommend a way to overcome
the limitation of this control.

Or is there a place to download software from the net that could help?

Thanks

Just declare something like:
POINT line[2];
then figure out the coordinates within your graph and
use Polyline();

For graph controls, you might want to see
http://www.fastech.com/prods/spc/fastspc.htm

--Brian