Prime calculation speed

[MarkusR]

Dim start As Double = System.Ticks

Var TotalNumbers As Integer = 100000

NumListBox.RemoveAllRows
PrimeListBox.RemoveAllRows

Var TempNum(-1) As String
Var TempPrime(-1) As String

For i As Integer = 0 To TotalNumbers
  TempNum.AddRow(Str(I))
  If IsPrime(I) Then
    TempPrime.AddRow(Str(I))
  End If
Next

NumListBox.AddRows(TempNum)
PrimeListBox.AddRows(TempPrime)

Var elapsedSeconds As Double = (Ticks - start) / 60
MessageBox("Time: " + elapsedSeconds.ToString)