Populating DataGridView With Correct Data

[VB 2008]. I'm trying to populate a DataGridView based on information in the Items in a ListBox (specifically, the file names without hypens or file extensions) and the content of the actual files. The DataGridView is supposed to look something like this:

IDNon-Hyphenated File NameFile Data
1. Some fileThe sky is blue.
2. Another fileThe grass is green.

The Items in the ListBox (lstFiles) look like this:
C:UsersUsernameDesktopFolderAsome-file.txt
C:UsersUsernameDesktopFolderAanother-file.txt

What is happening is that the DataGridView is being populated, but it looks like this:
IDNon-Hyphenated File NameFile Data
1 Another fileThe grass is green.
2 Another fileThe grass is green.

It's adding the second file's information to the DataTable twice and not adding the first file's information at all.

Private Sub btnDoSomething_Click(ByVal sender As Object, ByVal e As EventArgs) Handles btnDoSomething.Click
Dim pattern As String = "([w:\w /]([a-zA-Z0-9-]+?).w+)"
Dim reg As Regex = New Regex(pattern, RegexOptions.IgnoreCase)
Dim mat As Match
For Each Item In lstFiles.Items
[Code] .....