Adding Items to an array

Having a bit of trouble with the following code. I am attempting to create a drop down box that contains the contents of a list of cells. The cells aren't in a fixed location and there could be a different number of items depending on another list box. So the array can't be a fixed size. How can I add the items I want to the array and then display them in the combobox?

Thanks

Private Sub Categorybox_Change()
    Dim typ() As Integer
    Dim x As Integer
    Dim r As Integer
    Dim c As Integer
    c = 2
    r = 2
    x = 0
    
    Do While Cells(r, c) <> categorybox.Value
        r = r + 1
    Loop
    Do While Cells(r, c) = categorybox.Value
        ReDim typ(x + 1)
        typ(x) = Cells(r, (c + 1))
        x = x + 1
        r = r + 1
    Loop
    Typebox.List = typ()
End Sub