Is it better to use friend or public forms in vb.net? What are the advantages of each?
I notice when you import a vb6 project, the forms come in as friend, but when you add a new form in vb.net it is public. I have not seen any difference in the way they work, though, so I must be missing something.
If the form is Public it can be accessed from outside the current assembly (.exe). If it's Friend then it's only accessible from within the assembly. The same access level rules apply to Forms as other VB.NET classes.
I can't think of a common Winforms situation where you would need public Forms because they're usually in the same assembly making friend good enough. Unless you had forms scattered through different assemblies and they needed to reference one another.
Maybe the Microsoft team that wrote the import tool decided on Friend because all the forms came from the same classic project, whereas the Visual Studio (New Item) team decided on Public because the .NET way deals more with modularized projects. It might just be as simple as that.
In my opinion, I would use Friend (aka internal in C#) even though the default is public. I would also use private for controls on the form even though I think VB defaults to protected. In general, think of type/member access as if it were your wife's boobs. Keep them hidden from others up unless there's some benefit to exposing them (like getting out of a speeding ticket or making a shared library of common dialogs, etc.)
One drawback with making things internal is that you have to do some extra work to make them public to your unit tests. See the InternalsVisibleToAttribute for details.
VB6 did not support exporting forms from a class library. The natural mapping for converted code therefore is Friend. However, VB.NET has no such problems. Using Public is fine, assuming any exposed types in public method arguments is Public as well. Easy to find, the compiler will tell you.