Hi Trev,
It <is> an easy question - once you know - but it's far from stupid. This
issue (Forms versus Form classes) is a major stumbling block for many
programmers coming from VB6 to VB.NET.
The following is taken from an answer to someone a while back. It only
answers part of your question, but hopefully it will shed a bit of light on
the matter.
Forms are no longer just there. They have to be managed. What's worse is
that I'm not quite telling the truth. The .NET designers, in an effort to be
helpful, have hidden some of the code that, if it had to be done manually,
would make things clearer.
In C#, if you want a form, you have to code its declaration and its
instantiation and then show it. All C# programs start with their "Sub Main".
This creates the startup form and off you go. Being explicit means less
confusion.
In VB, if you don't use Sub Main as your starting point, the compiler
effectively creates it for you - behind the scenes. And thus the confusion
starts! Here you have an obviously visible form which has appeared out of
nowhere. There is no variable with which to access it from outside the form.
There is little (to a newcomer from VB6) to say that this Form1 is <not> the
form that you can see, but is the class (template) for the form.
Create a project with a single form, Form1 and this is what you get
(simplified)
Class Form1
Sub Main
Dim f As New Form1
Application.Run (f)
End Sub
Sub New
Sub Form1_Load
End Class
But you never get to see the Sub Main as this is done for you and hidden.
In VB6, Form1 would be the class <and> the instance. In VB.NET, Form1 is the
class <only> while f, the hidden variable, is the instance.
Let's put Sub Main into a module:
Module LetsGo
Public f As New Form1
Sub Main
Application.Run (f)
End Sub
End Module
Class Form1
Sub New
Sub Form1_Load
End Class
Now you have a global variable, f, which is the actual form. You can
access this variable from anywhere and use it to Show and Hide, etc.
Regards,
Fergus
