Different assemblies with the same assembly name, namespace and class? Use an extern alias (which is how different versions of the same assembly can be used if

Different assemblies with the same assembly name, namespace and class? Use an extern alias (which is how different versions of the same assembly can be used if necessary): https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/extern-alias https://docs.microsoft.com/en-us/dotnet/csharp/language-refe... Different assemblies with different assembly names but same namespace and class? Just use the fully qualified type name (and alias it for a shorter name). Single assembly/project and namespace with the same class in multiple files? If you're just spreading out the code then use partial classes, otherwise why would you define the same type twice? C# (and other languages) that use virtual namespaces can do everything that file-based namespaces can do, but also support many more scenarios.