About the VB.NET category

Programming languages VB.NET
#1

This subcategory is for VB.NET programmers. Don’t be shy, no question is too simple or too complicated.

Please, do not post here if your question is about a puzzle, a contest or anything that relates to the CodinGame platform (there are other categories for that purpose).

#2

when i use “ABS()” or any other math function i get this error message:
error VBNC30451: ‘ABS’ is not declared. It may be inaccessible due to its protection level…

#3 
Dim value1 As Integer = -1000
Dim abs1   As Integer = Math.Abs(value1)

Console.Error.WriteLine(value1)
Console.Error.WriteLine(abs1)

This code give me a right input.

#4

File folder, name, extention? etc, gives me an error