Search for file containing a word? [Resolved]

[ProgrammerJon]

I have this code:

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        ' make a reference to a directory
        Dim di As New IO.DirectoryInfo("c:\")
        Dim diar1 As IO.FileInfo() = di.GetFiles("test.txt")
        Dim dra As IO.FileInfo

        'list the names of all files in the specified directory
        For Each dra In diar1
            ListBox1.Items.Add(dra)
        Next
    End Sub

If I want to filter the search then I change di.GetFiles("righ here")
What do I do if I want to search for something similar to something.

ex.
If I wanted to search for files containg the word "Test" then what would I do?