Short circuiting by using AndAlso and OrElse

[Euvin]

I am kind of confuse as to how these operators work:
AndAlso and OrElse

Anyone care to explain. Some examples would be great!

[kimiraikkonen]

On Apr 14, 2:39 am, Euvin <[e-mail]:

I am kind of confuse as to how these operators work:
AndAlso and OrElse

Anyone care to explain. Some examples would be great!

Euving,
Take a look at this link for a brief explanation:

http://visualbasic.about.com/od/usin...vbnetlogop.htm

[=?Utf-8?B?RmFtaWx5IFRyZWUgTWlrZQ==?=]

A popular use of AndAlso would be something like this:

if ((anObj isnot Nothing) AndAlso (anObj.TheProperty = False)) then
' do some work
endif

With an ordinary "And" in the above, you would get an "Object not set..."
error in the second clause. The new syntax looks at the furst part, and
skips out when the object is not set.

OrElse is processed similarly. If the first part is true, then there is no
evaluation of the second part.

"Euvin" wrote:

I am kind of confuse as to how these operators work:
AndAlso and OrElse

Anyone care to explain. Some examples would be great!

[Steve Gerrard]

Euvin wrote:

I am kind of confuse as to how these operators work:
AndAlso and OrElse

Anyone care to explain. Some examples would be great!

A simple way to look at it:

If TestA AndAlso TestB Then
DoSomething
End If

is equivalent to

If TestA Then
If TestB Then
DoSomething
End If
End If

For OrElse, you get

If TestA OrElse TestB Then
DoSomething
End If

being equivalent to

If TestA Then
DoSomething
ElseIf TestB Then
DoSomething
End If

[Cor Ligthert[MVP]]

Euvin,

The AndAlso and the OrElse are the same as in every orther language the And
and the Or.

A strong lobby from the VB6 side made that in VB this was choosen those two
above instead of the Or and the And.
Despite that less important things were changed with the introduction of
VB2001 this was a main option for the VB6 side.

The reason was that probably in 0,01% of all programs the OR and AND are in
VB as well used for boolean operations.

Something as AndBool and OrBool they called a breaking change.

The behaviour of And And Or in VB is too a little bit else because of this,
because everything is evaluated first.

Cor

[Michel Posseth [MCP]]

Here the explanation of someone from the VB dev team ( Paul Vick software
architect of the VB Development team )

http://www.panopticoncentral.net/articles/919.aspx

and you wil see that

And & Or are used for bitwise comparisation

AndAlso & OrElse are used for logical comparisation

despite what people say or think it is clear that they took this idea from C
" like C where there are separate logical operators (|| &&) and bitwise
operators (| &)."

HTH

Michel
"Euvin" <jc*****@uncc.eduschreef in bericht
news:d6**********************************@2g2000hs n.googlegroups.com...

>I am kind of confuse as to how these operators work:
AndAlso and OrElse

Anyone care to explain. Some examples would be great!

[Herfried K. Wagner [MVP]]

"Euvin" <jc*****@uncc.eduschrieb:

>I am kind of confuse as to how these operators work:
AndAlso and OrElse

Place the caret on 'AndAlso' or 'OrElse' and press the F1 key in the IDE's
text editor.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

[Cor Ligthert[MVP]]

Michel,

C is using || and &&.
The the shortcutted Or and And are much older: it was already in the first
versions of Cobol.

:-)

Cor

"Michel Posseth [MCP]" <MS**@posseth.comschreef in bericht
news:OM*************@TK2MSFTNGP05.phx.gbl...

Here the explanation of someone from the VB dev team ( Paul Vick software
architect of the VB Development team )

http://www.panopticoncentral.net/articles/919.aspx

and you wil see that

And & Or are used for bitwise comparisation

AndAlso & OrElse are used for logical comparisation

despite what people say or think it is clear that they took this idea from
C " like C where there are separate logical operators (|| &&) and bitwise
operators (| &)."

HTH

Michel
"Euvin" <jc*****@uncc.eduschreef in bericht
news:d6**********************************@2g2000hs n.googlegroups.com...

>>I am kind of confuse as to how these operators work:
AndAlso and OrElse

Anyone care to explain. Some examples would be great!

[Michel Posseth [MCP]]

>>it was already in the first versions of Cobol.

Yes i know that we have just rewritten a production system from Cobol so i
have seen some familiair constructs in these sources , as we had to rewite
the system from printed out Cobol source

However my point is that from origin most MS developers are C proggers and
if you read most MS DEV blogs you read that they took ideas from there
background "C" and introduced it to VB

Michel
"Cor Ligthert[MVP]" <no************@planet.nlschreef in bericht
news:35**********************************@microsof t.com...

Michel,

C is using || and &&.
The the shortcutted Or and And are much older: it was already in the first
versions of Cobol.

:-)

Cor

"Michel Posseth [MCP]" <MS**@posseth.comschreef in bericht
news:OM*************@TK2MSFTNGP05.phx.gbl...

>Here the explanation of someone from the VB dev team ( Paul Vick
software architect of the VB Development team )

http://www.panopticoncentral.net/articles/919.aspx

and you wil see that

And & Or are used for bitwise comparisation

AndAlso & OrElse are used for logical comparisation

despite what people say or think it is clear that they took this idea
from C " like C where there are separate logical operators (|| &&) and
bitwise operators (| &)."

HTH

Michel
"Euvin" <jc*****@uncc.eduschreef in bericht
news:d6**********************************@2g2000h sn.googlegroups.com...

>>>I am kind of confuse as to how these operators work:
AndAlso and OrElse

Anyone care to explain. Some examples would be great!