Auto-populate Userform From Course List

Some Background info:
This is my first post! I am a total novice when it comes to VBA in Excel (but I'm a fast learner!), so please bear with me if my question is either obvious or easy (or if this is a question that's been asked 14980213 times already). I have some programming experience, but all in C or C++, not in VBA--this makes the project challenging. I also have to hand this off in a few months and trust that it'll never break, ever--more challenging.

I'm trying to make a Participant Tracking System for some workshops we offer. The intent is to make a userform so that an administrator can input all the information for the participant in question. One important question on the form is which course the participant intends to take; the snag is that the current list may change over time.

The Spreadsheet is set up with Course headings starting at R8C8, and continuing across for all 16 courses we currently offer. The data for the participant is entered into Rows 1-7, and the date they completed the course in the appropriate column for that course. There are some formulas in Rows 1-7, the important one here counts up the number of classes currently offered.

So, below is the code i'm trying to use, at least to start. I am making a combobox that has all of the available classes.


Private Sub UserForm_Initialize()

Dim ClassList() As String

'R5C6 contains a formula that calculates the number of classes offered. The value is currently 16
Redim ClassList(R5C6)

iCount = 0
y = 8

Do While iCount > R5C6
'R8C8 is where the class list begins.
'It continues horizontally along the rows for the 16 titles offered.
Range(R8Cy).Select
ClassList(iCount) = ActiveCell
y = y + 1
iCount = iCount + 1
Loop

With ClassListBox
.Clear
.List = ClassList
.ListIndex = -1
End With

End Sub

I used to have a line that replaced the following chunk.


Range(R8Cy).Select
ClassList(iCount) = ActiveCell

It read


ClassList(iCount) = R8Cy

and did nothing for me at all.

When I initialize the userform, I get a blank combobox. It doesn't do what I want it to do, but that's probably because I'm telling it to do something weird.