abstract class in VB.NET?

[bungpeng]

Can I define a "Abstract" class in VB.NET?

It means I do not need to create a object to refers to this class; I can direct use the methods/functions of the class without declared any object.

I use it before in "Java"

 

[Divil]

You can declare static members of a class using the Shared keyword in VB.NET:

Public Class Class1
  Public Shared Sub Boo()
  End Sub
End Class

You would then be able to call Class1.Boo() without an instance of the class.

 

[bungpeng]

Is it? I though this is only a static variable type in normal class?

 

[Divil]

Static variables in vb.net remain in existence and retain their latest values after termination of the procedure in which they are declared. They are not the same as shared members of classes.

 

[bungpeng]

I not quite undertanding, then what different between static variables and shared variables?

How do I declare static variable? with Static keyword?

 

[Volte]

Static var As Integer

When the variables go out of scope, they retain their values (though
cant be accessed from outside of the procedure theyre declared in).

The term Static comes from the fact that the variable keeps
a static location in memory, thus preserving the data.

 

[bungpeng]

You mean "Shared" and "Static" are the same, the only different is that Static cant be access from outside the procedure? right?

Actually what is the purpose for Microsoft to do that? Why dont use the same? either Shared or Static?

 

[Volte]

No, Shared means that a sub inside a class can be accessed from
anywhere, without declaring an instance of the class. In VB6, a
public method in a module did what a shared method in a class
does in VB.NET; although modules still exist in .NET, you should
use Shared methods in classes.

 

[bungpeng]

In this case: I create a class Car with 2 functions A and B. A declare as "Shared", B is normal public function.

If I want to access these functions (A and B), then do I need to create object for class Car?

This is what I confuse now....

Sorry because disturb you again...

 

[Divil]

All this information is covered in great details in the help file, within the Visual Basic .NET language reference.

 

[bungpeng]

Which part of Help file?

 

[Nerseus]

I believe he said the Language Reference. Check out the keyword "Shared", "Static" etc. and read as much as you can - there is a GREAT deal of info around the class and member modifiers (such as public, private, shared, etc.). Its well worth the effort to spend 8 hours or so writing small sample classes and seeing what each keyword does and doesnt do. A book on VB.NET would cover this as well with good samples.

-Nerseus

 

[bungpeng]

I try to read more detail, i hope this is what i want...