Start VB.NET GUI app using Sub Main or form startup object?

Question

Is there any reason to start a GUI program (application for Windows) written in VB.NET in the Sub Main of a module rather than directly in a form?

EDIT: The program

Answer 1

Yes, and I have done it a few times.

One reason is, that if your app is COM EXE (speaking now from a VB6 point of view) then you want to be able to detect in what context the EXE is being called (being launched or being spoken to by some other app).

For example:

Sub Main()
    If App.StartMode = vbSModeAutomation Then
        ...
    Else
        ...
    End If
End Sub

Another is if you want your app to be able to handle any command line parameters.

For example:

Sub Main()
    If App.PrevInstance Then End
    If InStr(Command, "/s") > 0 Then
        Form1.Show
    ElseIf InStr(Command, "/p") > 0 Then
        LoadPicture ("c:\windows\Zapotec.bmp")
    End If
End Sub

(from one of my attempts to make a screen saver)