'View Docs
ViewType = 12
Dim FileDialog1 As FileDialog
FileDialog1.FilePath = File.DirRootExternal
If FileDialog1.Show("Select file", "Ok", "Cancel", "", Null) = DialogResponse.POSITIVE Then
Dim in As Intent
in.Initialize(in.ACTION_VIEW, "file://" & File.Combine(FileDialog1.FilePath , FileDialog1.ChosenName))
Dim Ext As String
Ext = FileDialog1.ChosenName.SubString(FileDialog1.ChosenName.IndexOf(".") + 1)
in.SetType("application/" & Ext)
in.WrapAsIntentChooser("Select application")
StartActivity(in)
End If