ASP.NET visual basic undefined functions - asp.net

Question

I'm converting a bunch of foxweb programs to asp.net. Some of the functions I invoke in the asp code use "external functions," by which I mean functions that I have defined in .vb files. For example, FileExists() is a nice function I would like to pull out into a common thing called clsCommon.vb .
I have implemented it like this:
Option Explicit On
Option Strict On
Imports System
Imports System.Web.UI
Imports System.Web.UI.Page
Public Class clsCommon
Inherits Page
Public Shared Function FileExists(ByVal filename As String) As Boolean
If Dir$(filename) <> "" Then
Return True
Else
Return False
End If
End Function
End Class
I have tried using both DIR$() and DIR(). In each case, the error returned on the web page reads:
Compiler Error Message: BC30451: Name 'Dir' is not declared.
As with other functions I have written I invoke FileExists() something like this:
<%# page Debug="true" inherits="clsCommon" src="clsCommon.vb" %>
<%
Dim filename as String = "example.txt"
If clsCommon.FileExists(filename) then
Response.Write(filename & " Exists")
else
Response.Write(filename & " does not Exist")
end if
%>
Note 1: While I want to solve this specific problem, what I'm really looking for is the general way to get to these functions like DIR(), CHR(), etc., that I have come to rely on in VB.
Note 2: asp seems to only look at the vb text file - and not at the compiled dll file, so I don't think the references I use have any effect on it.
Anyone see what I'm missing?

Answer 1

TheGeekYouNeed is certainly right. The best approach is to either keep your code in VB (if it ain't broke, don't fix it) or consider investing some time in learning .Net
I have seen code conversion tools for turning VB code into VB.Net. I can't imagine them working for non-trivial projects though. Likewise, you can go out of your way to keep your code as 'VB like' as possible, but I think it's like burning down your house to avoid having to sweep the floor.
Anyway, the DIR function does still exist in the Microsoft.VisualBasic namespace.
http://msdn.microsoft.com/en-us/library/dk008ty4(v=vs.71).aspx
The more generally accepted way of doing this in .NET would be to use File.Exists
http://msdn.microsoft.com/en-us/library/system.io.file.exists.aspx

Answer 2

You are using VB.Net ... not VB. There are differences, and you need to use the .Net framework appropriately.
Programming is always a lesson of learning.

Answer 3

Solution: Figure out what function / method I need & search for it on msdn
When I find the function as in:
http://msdn.microsoft.com/en-us/library/microsoft.visualbasic.strings.chr.aspx
There will be a line that says, for example,
Namespace: Microsoft.VisualBasic
Use that name with an "Imports" near the beginning of the VB file, before the class definition as follows:
Option Explicit On
Option Strict On
Imports System
Imports System.Web.UI
Imports System.Web.UI.Page
' The two critical lines follow:
Imports System.IO
Imports Microsoft.VisualBasic
Public Class clsCommon
Inherits Page
Public Shared Sub TestExistence(ByVal filename As String)
if NOT File.Exists(filename) then
' ... do something.
end if
End Sub
Public Shared Function TestCHR(ByVal str As String) as string
return str & chr(13) & chr(10) 'just an example
End Function
End Class
MicroSoft.VisualBasic was required by the CHR() function
and System.IO was required by the File.Exists() function.