vb.net 簡單的年月間隔涵數 線上等,急!

Dim StartYear As Long = 2018

Dim StartMonth As Long =8

Dim EndYear As Long = 2019

Dim EndMonth As Long = 3

一個涵數
function(StartYear,StartMonth,EndYear,EndMonth)

出來結果為

str="2018/8,2018/9,2018/10,2018/11,2018/12,2019/1,2019/2,2019/3,2019/4"

function(StartYear,StartMonth,EndYear,EndMonth) as string
dim r as string = ""
dim dt as datetime = new datetime(startyear, startmonth, 1)
while dt <= new datetime(endyear, endmonth, 1)
r += dt.tostring("yyyy/MM") + ","
dt = dt.Addmonth(1)
end while
if right(r, 1) = "," then r = left(r, len(r) - 1)
return r
end function