Probao sam sa ovim kodom, ali ne radi...
Code:
Public Shared Sub ChangeConnectionString(ByVal strConn As String)
Dim _config As Configuration = ConfigurationManager.OpenExeConfiguration(ConfigurationUserLevel.None)
_config.AppSettings.Settings.Remove("connString")
_config.AppSettings.Settings.Add("connString", strConn)
_config.Save(ConfigurationSaveMode.Modified)
ConfigurationManager.RefreshSection("appSettings")
End Sub