This can be done using variable resistor and variable capacitor etc and then controlling both R and C through a common 'source' like real expression. But this becomes very indirect way to do this.

Suppose I have a simple R-C circuit to simulate. I have created the circuit connection in OpenModelica Graphic editor. I want to assign values of  R and C as function of a real parameter, say k.  Let's say I want R=10*k  and  C=.001*k .

I want to be able to have some graphical component  in which I can give some value of k, say 100. How can I do it?

Please note that I can always go to 'text view' and add an statement

parameter Real k = 100;

and it can be done. BUT I want to be able to do this graphically.