How to determine if a object type is a built in system type

Question

I am writing a simple List to CSV converter. My converter checks the all the t\'s in List and grabs all public properties and places them

Answer 1

Namespace-based methods potentially may cause collisions.

There is an another reliable and simple way:

static bool IsSystemType(this Type type) => type.Assembly == typeof(object).Assembly;

Or a little bit more optimal, caching the system assembly:

static readonly Assembly SystemAssembly = typeof(object).Assembly;

static bool IsSystemType(this Type type) => type.Assembly == SystemAssembly;

Answer 2

I prefer

colType.FullName.StartsWith("System")

rather then

colType.Namespace.StartsWith("System")

becose Namespace may be null.