Variable '' is used before it has been assigned a value. - vb.net

Question

I'm trying to make a program that downloads a bunch of domains and adds them windows hosts file but I'm having a bit of trouble. I keep getting an error when I try storing them in a list. I don't get why it doesn't work.
Sub Main()
Console.Title = "NoTrack blocklist to Windows Hosts File Converter"
Console.WriteLine("Downloading . . . ")
Dim FileDelete As String = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile) & "/Downloads" & "/notracktemp.txt"
If System.IO.File.Exists(FileDelete) = True Then
System.IO.File.Delete(FileDelete)
End If
download()
Threading.Thread.Sleep(1000)
Dim s As New IO.StreamReader(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile) & "/Downloads" & "/notracktemp.txt", True)
Dim tempRead As String ' = s.ReadLine
Dim tempSplit As String() ' = tempRead.Split(New Char() {" "})
Dim i As Integer = 0
Dim tempStore As String()
s.ReadLine()
s.ReadLine()
Do Until s.EndOfStream = True
tempRead = s.ReadLine
tempSplit = tempRead.Split(New Char() {" "})
Console.WriteLine(tempSplit(0))
tempStore(i) = tempSplit(0)'The part that gives me the error
i = i + 1
Loop
Console.ReadKey()
End Sub
Sub download()
Dim localDir As String = Environment.GetFolderPath(Environment.SpecialFolder.UserProfile)
'"Enter file URL"
Dim url As String = "https://quidsup.net/notrack/blocklist.php?download"
'"Enter directory"
Dim dirr As String = localDir & "/Downloads" & "/notracktemp.txt"
My.Computer.Network.DownloadFile(url, dirr)
'System.IO.File.Delete(localDir & "/notracktemp.txt")
End Sub

Answer 1

tempStore() has to have a size
count number of lines in file with loop, then declare it as tempStore(i) where i is the amount of lines. Here is a function that counts the lines.
Function countlines()
Dim count As Integer
Dim s As New IO.StreamReader(Environment.GetFolderPath(Environment.SpecialFolder.UserProfile) & "/Downloads" & "/notracktemp.txt", True)
s.ReadLine()
s.ReadLine()
count = 0
Do Until s.EndOfStream = True
s.ReadLine()
count = count + 1
Loop
Console.WriteLine(count)
Return count
Console.ReadKey()
End Function
Then what you do is:
Dim count As Integer
count = countlines()
Dim tempStore(count) As String