Public variable not the same as using a property?

[dgk]

If I have a class with a public variable, isn't this the same as a
private variable with a property? ie, isn't this:

Public Class MyTest
Public MyVar as String
End Class

the same as this:

Public Class MyTest
Private _MyVar as String
Property MyVar
Get
Return _MyVar
End Get
Set (byval value as String)
_MyVar = value
End Set
End Property
End Class
I always thought so, in fact, I thought that the complier converted
the first into the second.

Yet, when I try to databind a generic list of MyTest to a gridview
using the first syntax, it fails. When I use the second syntax it
succeeds.

Does anyone know why?

[Cor Ligthert[MVP]]

dgk,

My message could be read wrong, what I mean is.

Why are you asking here questions while you have already in "advance" your
"own" incorrect answers and start discussing those as true?

Cor

"Cor Ligthert[MVP]" <no************ @planet.nlschre ef in bericht
news:E9******** *************** ***********@mic rosoft.com...

dgk,

What do you want to ask when you have already your (incorrect) answers.

Cor

"dgk" <dg*@somewhere. comschreef in bericht
news:qn******** *************** *********@4ax.c om...

>On Fri, 14 Sep 2007 08:55:28 -0500, "PvdG42" <pv**@toadstool .edu>
wrote:

>>>"dgk" <dg*@somewhere. comwrote in message
news:k8***** *************** ************@4a x.com...
If I have a class with a public variable, isn't this the same as a
private variable with a property? ie, isn't this:

Public Class MyTest
Public MyVar as String
End Class

the same as this:

Public Class MyTest
Private _MyVar as String
Property MyVar
Get
Return _MyVar
End Get
Set (byval value as String)
_MyVar = value
End Set
End Property
End Class
I always thought so, in fact, I thought that the complier converted
the first into the second.

Yet, when I try to databind a generic list of MyTest to a gridview
using the first syntax, it fails. When I use the second syntax it
succeeds.

Does anyone know why?

From a design perspective, they are very different. And IMHO, you should
consider the difference.
If you declare the variable as public, you are giving unrestricted access
to
that variable to code outside the class, thus exposing the variable to
potential corruption and breaking encapsulation. By declaring the
variable
private, then supplying a public property in your class, you have the
opportunit y and ability to control access to that variable by either not
providing a Set block, or by adding logic in the Set block that will
disallow illogical values.

Well sure, but if you don't care what comes in or goes out, then it's
a lot cleaner to just declare a public variable. Also quicker to type.
One line instead of six or seven (even if using a snippet).

One of the things I don't like about VB is that Readonly on the
property. I mean, if there's no Set, then it's readonly. I'm sure they
did that for a reason but I can't figure out why.
Well, anyway, if you're planning on using Databind, don't use public
properties.

[dgk]

On Mon, 17 Sep 2007 01:46:39 +0200, "Cor Ligthert[MVP]"
<no************ @planet.nlwrote :

>dgk,

My message could be read wrong, what I mean is.

Why are you asking here questions while you have already in "advance" your
"own" incorrect answers and start discussing those as true?

Cor

"Cor Ligthert[MVP]" <no************ @planet.nlschre ef in bericht
news:E9******* *************** ************@mi crosoft.com...

I'm not sure what you mean by discussing my own incorrect answers as
being true. I spent quite some time (a few hours) puzzling out why a
generic List (of X) wouldn't work as a datasource for a gridview. It
seemed to have built in rows and columns and it seemed to me that it
should work. I thought that perhaps I could save someone else from
wasting time.

>dgk,

What do you want to ask when you have already your (incorrect) answers.

Cor

"dgk" <dg*@somewhere. comschreef in bericht
news:qn******* *************** **********@4ax. com...

>>On Fri, 14 Sep 2007 08:55:28 -0500, "PvdG42" <pv**@toadstool .edu>
wrote:

"dgk" <dg*@somewhere. comwrote in message
news:k8**** *************** *************@4 ax.com...
If I have a class with a public variable, isn't this the same as a
private variable with a property? ie, isn't this:
>
Public Class MyTest
Public MyVar as String
End Class
>
the same as this:
>
Public Class MyTest
Private _MyVar as String
Property MyVar
Get
Return _MyVar
End Get
Set (byval value as String)
_MyVar = value
End Set
End Property
End Class
>
>
I always thought so, in fact, I thought that the complier converted
the first into the second.
>
Yet, when I try to databind a generic list of MyTest to a gridview
using the first syntax, it fails. When I use the second syntax it
succeeds.
>
Does anyone know why?

From a design perspective, they are very different. And IMHO, you should
consider the difference.
If you declare the variable as public, you are giving unrestricted access
to
that variable to code outside the class, thus exposing the variable to
potential corruption and breaking encapsulation. By declaring the
variable
private, then supplying a public property in your class, you have the
opportuni ty and ability to control access to that variable by either not
providing a Set block, or by adding logic in the Set block that will
disallow illogical values.

Well sure, but if you don't care what comes in or goes out, then it's
a lot cleaner to just declare a public variable. Also quicker to type.
One line instead of six or seven (even if using a snippet).

One of the things I don't like about VB is that Readonly on the
property. I mean, if there's no Set, then it's readonly. I'm sure they
did that for a reason but I can't figure out why.
Well, anyway, if you're planning on using Databind, don't use public
properties.