IsNothing showing error VB.NET VS2017 Community - vb.net

Question

My first post here and really basic question as I have just started learning.
I am following a step by step tutorial from youtube. https://www.youtube.com/watch?v=6utWyl8agDY code is working alright in the video. below is the code:
Imports System
Imports System.IO
Module Program
Sub Main()
Dim myReader As StreamReader = New StreamReader("values.txt")
Dim line As String = ""
While Not IsNothing(line)
line = myReader.ReadLine()
If Not IsNothing(line) Then
Console.WriteLine(line)
End If
End While
myReader.Close()
Console.ReadLine()
End Sub
End Module
Problem I am facing is that I have red error (squiggly) line under IsNothing. One thing to note is the in the video tutorial version of VS under use is 2013 while I am using VS2017 community. any idea what I am doing wrong here?

Answer 1

I'm not sure what your tutorial says but there are issues with that code. It's fairly poorly structured and, to be honest, you shouldn't really use IsNothing anyway. The most immediate issue is where you're reading the text and that you're testing for Nothing twice. The code would be better written like this:
Dim myReader As New StreamReader("values.txt")
Dim line As String = myReader.ReadLine()
While line IsNot Nothing
Console.WriteLine(line)
line = myReader.ReadLine()
End While
myReader.Close()
Console.ReadLine()
Comparing directly to Nothing using Is or IsNot is the way to go and there's also no need for that check inside the loop.
If you want to get a bit more advanced, you can also create the StreamReader with a Using statement, so it gets closed implicitly:
Using myReader As New StreamReader("values.txt")
Dim line As String = myReader.ReadLine()
While line IsNot Nothing
Console.WriteLine(line)
line = myReader.ReadLine()
End While
End Using
Console.ReadLine()
Better still would be to not create the StreamReader yourself at all but let the Framework do that for you:
For Each line As String In File.ReadLines("values.txt")
Console.WriteLine(line)
End Using
Console.ReadLine()
Note that that code uses ReadLines rather than ReadAllLines. Both would work but the former will only read one line at a time while the latter will read the whole file first, load the lines into an array and return that. In this case it probably doesn't really matter which you use but ReadLines is generally preferable unless you specifically need all the lines first or you want to loop over them multiple times.

Answer 2

You have to decide whether your console application requires .net Core or .net Framework is sufficient.
As others have written in responses, your code is in need of improvement.
However, your code will run correctly if you choose the .net framework for your new project in Visual Studio 2017 Community as shown in the screenshot below.