Unable to use File read and write in c# .net

Question

For some reason, I'm unable to use File read and write in c# .net, error display like below

Where I do have the System.IO.Compression.FileSystem under my Reference

Does anyone know why and how could I resolve this issue?

Answer 1

That File is referring to the Controller.File method.

It's enough to fully qualify the type:

var sw = System.IO.File.CreateText(filePath);