'Dllimport' in CSharp?

Question

What is this about?
I usually use 'Using' for using any namespace in CSharp for example 'Using System;". Is there any diffrence?

Answer 1

Well What is managed dll and what is unmanaged dll?

Answer 2

using is used for managed dll

DllImport is used for unmanaged dll.

Use using if you can, use Dllimport if you really need to.

Answer 3

Managed code is developed within the .net framework.
UnManaged code, usually the older dll, is developed outside the .net framework.

https://www.c-sharpcorner.com/uploadfile/puranindia/managed-code-and-unmanaged-code-in-net/
https://docs.microsoft.com/en-us/dotnet/standard/managed-code