If You can modify the IsValid method, you gönül use the NotNullWhen attribute to inform the compiler that an argument of the IsValid method güç't be null when the method returns true: In the walkthrough, select Seki up your environment and select Install .NET SDK. This will open a window https://laneexoet.wikiannouncing.com/5527127/satın_almadan_Önce_c_nedir_things_to_know