search multiple files by extension file name

Dim FExtension1 As String = "*.txt"
Dim FExtension2 As String = "*.exe"
Dim FExtension3 As String = "*.sys"

For Each file1 In IO.Directory.GetFiles(Dir, FExtension1)
    ' add to list box or append to text box or a Datagridview
Next

For Each file1 In IO.Directory.GetFiles(Dir, FExtension2)
    ' add to list box or append to text box or a Datagridview
Next

For Each file1 In IO.Directory.GetFiles(Dir, FExtension3)
    ' add to list box or append to text box or a Datagridview
Next