Dim strOriginal As String = "PcKULT.NET - Manipulation de String sous .NET"
Dim strModified As String = String.Empty
Parcourir chaque caractère de votre chaîne
For i As Integer = 0 To strOriginal.Length - 1
MessageBox.Show(strOriginal(i).ToString())
Next i
For Each c As Char In strOriginal
MessageBox.Show(c.ToString())
Next c