Beginner question about generics

Are these two statments equivalent?

Public Class Class2(Of X As Class1)
Public Class Class2(Of X As {Class1})

What doe开发者_如何学Cs the "New" mean?

Public Class Class2(Of X As {Class1, New})

Your first two statements are equivalent. The curly brackets are how to use multiple generic constraints in VB.NET. In your case even though there are brackets, there is only a single constraint.

The New keyword is a constraint that ensures the type T has a constructor that takes no parameters. So your second definition ensures that T is or inherits from Class1 and has parameterless constructor.

Read these links:

• Class Statement Syntax
• Type List Description
• New Keyword Explanantion