You should define all default properties with a prefix (eg: def_TempDir) Then you can do thomething like:
Enum EN_PropertyType
User
Application
End Enum
Sub LoadSettingsIntoControls(typ As EN_PropertyType)
For Each ctl In Me.Controls
If ctl.GetType = (New TextBox).GetType Then
Dim SettingName As String = ""
Select Case typ
Case EN_PropertyType.Application
SettingName = "def_" & Mid(ctl.name, 4)
Case EN_PropertyType.User
SettingName = Mid(ctl.name, 4)
End Select
ctl.Text = My.Settings.Item(SettingName)
End If
Next
End Sub