Usage of the "New" KeyWord

[Sam]

Hi everyone

Could anyone help me understand the usage of the "New" keyword I'm new to
VB.Net.

1. Why do we use the "New" keyword on some object type variables such as the
myPen of the example below and not with the bgColor. Both the Pen and Color
are objects

Dim myPen As Pen = New Pen(Color.AquaM arine)
Dim bgColor As Color = Color.LightYell ow

2. Why do properties such as Size, Location, Font... of controls require a
new instance of their classes when we want to change their properites at run
time


Thanks

Sam

[William Ryan eMVP]

Re: Usage of the "New&qu ot; KeyWord

Color is a Structure, hence a ValueType whereas Pen is a Reference type.
Everythign in .NET is an 'object' btw. That's why even though integer is an
object , Dim i as Integer is ok. This may help a little if you aren't
familiar with the distinction

http://www.knowdotnet.com/articles/referencetypes2.html

The difference in behavior between valuetypes and referencetypes is NOT
trivial by any means, but understanding the differences is pretty
straightforward . For instance, pass in a Value Type by value to function
and modify it, the original is still in tact. Pass in a Reference Type
ByVal to a method and any changes made to it are made to the object you
passed in.

I'm not sure I totally understand your second question but I'll take a
guess. Those properties are instance properties, meaning they belong to the
instance. Other properties are static (shared in VB) which means they
belong to the class and not a specific instance.

HTh,

Bill

--
W.G. Ryan MVP Windows - Embedded

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"Sam" <qdo@datawave.c a> wrote in message
news:Oztn9IndEH A.2812@tk2msftn gp13.phx.gbl...[color=blue]
> Hi everyone
>
> Could anyone help me understand the usage of the "New" keyword I'm new[/color]
to[color=blue]
> VB.Net.
>
> 1. Why do we use the "New" keyword on some object type variables such as[/color]
the[color=blue]
> myPen of the example below and not with the bgColor. Both the Pen and[/color]
Color[color=blue]
> are objects
>
> Dim myPen As Pen = New Pen(Color.AquaM arine)
> Dim bgColor As Color = Color.LightYell ow
>
> 2. Why do properties such as Size, Location, Font... of controls require a
> new instance of their classes when we want to change their properites at[/color]
run[color=blue]
> time
>
>
> Thanks
>
> Sam
>
>[/color]