Having one form directly change the appearance of another form is bad OO design. It couples the forms tightly. You should pass back information to the form so it can change itself.
That said, by default C# controls are private. If you click on the control and look in the Design section of the properties you'll see a 'Modifier' parameter set to 'private'. You can make this 'public' and it will act like the VB form. This, too, is bad design as you should make properties to access the controls :)
As for the repeated code, create a helper class to hold the methods. Call the methods to get the data you need.