Thetype exposes the following members.
The type of device for which the Chooser will select a driver. (String, default = "Telescope")
Select ASCOM driver to use without pre-selecting in the dropdown list
Select ASCOM driver to use including pre-selecting one in the dropdown list
Cleans up and disposes objects used by Chooser
Calling Chooser.Choose() causes a chooser window to appear, with a drop down selector list containing all of the registered Telescope drivers, listed by the driver's friendly/display name. The user sees a list of telescope types and selects one. Before the OK button will light up, however, the user must click the Setup button, causing the selected driver's setup dialog to appear (it calls the driver's Telescope.SetupDialog() method). When the setup dialog is closed, the OK button will light and allow the user to close the Chooser itself.
The Choose() method returns the DriverID of the selected driver. Choose() allows you to optionally pass the DriverID of a "current" driver (you probably save this in the registry), and the corresponding telescope type is pre-selected in the Chooser's list. In this case, the OK button starts out enabled (lit-up); the assumption is that the pre-selected driver has already been configured.