Hi Claude,
Please note that you need to include the
Telerik.WinControls.Enumerations namespace if you want to work with
ToggleState.On only.
If you do not include the
Telerik.WinControls.Enumerations namespace, you should set the toggle state as shown below:
I hope this helps. If you have additional questions, feel free to contact me.
Greetings,
Nikolay
the Telerik team