When to use AndAlso vs And ?

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

Greetings,

If x = y And m = n The
....
End If

If x = y AndAlso m = n Then
....
End If

When do I need to use AndAlso vs And?

Thanks,
Rich

[=?Utf-8?B?RGF2aWQgQW50b24=?=]

RE: When to use AndAlso vs And ?

For the sample you provided, you are doing a strictly logical operation. Use
the "AndAlso" since it's more efficient (it doesn't evaluate the second
operand if the first is false).
The "And" operator is usually just used for bitwise operations. You can
also use "And" for logical operations, but it evaluates both operands always.
--
David Anton

https://www.tangiblesoftwaresolutions.com

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"Rich" wrote:

Greetings,
>
If x = y And m = n The
...
End If
>
If x = y AndAlso m = n Then
...
End If
>
When do I need to use AndAlso vs And?
>
Thanks,
Rich

[RobinS]

Re: When to use AndAlso vs And ?

If you use "And", then it processes all of the clauses and then decides
if it's true or not.
So it checks both (x=y) and (m=n).

If you use "AndAlso", it stops processing when it hits a condition that
is false. So if (x=y)
is false, it never checks (m=n). This is more efficient because it
doesn't do
unnecessary processing, and also can be handy, if you want to do
something like this:

If (rdr IsNot Nothing) AndAlso rdr.Rows(0).Ite ms(0).ToString = "abc" ...

Unlike VB6, it won't crap out if rdr is nothing, because it won't
process the
second clause.

For the "or" operator, they added "OrElse" which does the same thing.
It's called short-circuiting.

I believe this is the way "and" and "or" work in C/C++/C#. I think they
would
have just changed "and" and "or" in VB, but it would have freaked out
too many
people and required more work when converting from VB6, so they just
added
new constructs.

Robin S.
(more info than you wanted, wasn't it?)
------------------------------

"Rich" <Rich@discussio ns.microsoft.co mwrote in message
news:82705A82-37C8-40E3-B613-64AAF8158802@mi crosoft.com...

Greetings,
>
If x = y And m = n The
...
End If
>
If x = y AndAlso m = n Then
...
End If
>
When do I need to use AndAlso vs And?
>
Thanks,
Rich

[aaron.kempf@gmail.com]

Re: When to use AndAlso vs And ?

what a load of crap it worked well enough in VB6

unnecessary change isn't good.
it's unnecessary

-Aaron


RobinS wrote:

If you use "And", then it processes all of the clauses and then decides
if it's true or not.
So it checks both (x=y) and (m=n).
>
If you use "AndAlso", it stops processing when it hits a condition that
is false. So if (x=y)
is false, it never checks (m=n). This is more efficient because it
doesn't do
unnecessary processing, and also can be handy, if you want to do
something like this:
>
If (rdr IsNot Nothing) AndAlso rdr.Rows(0).Ite ms(0).ToString = "abc" ...
>
Unlike VB6, it won't crap out if rdr is nothing, because it won't
process the
second clause.
>
For the "or" operator, they added "OrElse" which does the same thing.
It's called short-circuiting.
>
I believe this is the way "and" and "or" work in C/C++/C#. I think they
would
have just changed "and" and "or" in VB, but it would have freaked out
too many
people and required more work when converting from VB6, so they just
added
new constructs.
>
Robin S.
(more info than you wanted, wasn't it?)
------------------------------
>
"Rich" <Rich@discussio ns.microsoft.co mwrote in message
news:82705A82-37C8-40E3-B613-64AAF8158802@mi crosoft.com...

Greetings,

If x = y And m = n The
...
End If

If x = y AndAlso m = n Then
...
End If

When do I need to use AndAlso vs And?

Thanks,
Rich

[Chris Dunaway]

Re: When to use AndAlso vs And ?

aaron.kempf@gma il.com wrote:

what a load of crap it worked well enough in VB6

Really? How would VB6 handle this code if the instance were null?

If (Not obj Is Nothing) And (obj.Property = "something" ) Then
'Do something here
End If

It would have crashed because IIRC, And was not short circuited in VB6
.. Using AndAlso avoids this in VB.Net.

>
unnecessary change isn't good.
it's unnecessary

The original VB.Net beta proposed adding two new operators called
BitAnd and BitOr which would be used for bitwise operations and
changing And and Or to only be logical operations. That would have
been an unnecessary change and, thankfully, they changed it back.

>

"Rich" <Rich@discussio ns.microsoft.co mwrote in message

>
When do I need to use AndAlso vs And?

[Chris Dunaway]

Re: When to use AndAlso vs And ?

Rich wrote:

>
When do I need to use AndAlso vs And?
>

RobinS explained how those keywords work so I won't repeat that
information. My recommendation is to ALWAYS use AndAlso and OrElse
when doing logical comparisons. It costs you nothing to use them and
you get the benefits of short circuiting.

Use And and Or for bitwise operations.

The exception being if you are reusing code from VB6 and it might not
be worth the time to change the And's and Or's to AndAlso and OrElse.

Chris

[aaron.kempf@gmail.com]

Re: When to use AndAlso vs And ?

and you seriously can't find a workaround for that?

I'd wrap it in a function and be done with it. lol
shit can you seriously not figure out the logic here?

Public Function DoSomething(obj as object) as boolean
on error resume next

If obj.property <"something"
DoSomething = False
Else
DoSomething = True
end select

End function

Chris Dunaway wrote:

aaron.kempf@gma il.com wrote:

what a load of crap it worked well enough in VB6

>
Really? How would VB6 handle this code if the instance were null?
>
If (Not obj Is Nothing) And (obj.Property = "something" ) Then
'Do something here
End If
>
It would have crashed because IIRC, And was not short circuited in VB6
. Using AndAlso avoids this in VB.Net.
>

unnecessary change isn't good.
it's unnecessary

>
The original VB.Net beta proposed adding two new operators called
BitAnd and BitOr which would be used for bitwise operations and
changing And and Or to only be logical operations. That would have
been an unnecessary change and, thankfully, they changed it back.
>

>
"Rich" <Rich@discussio ns.microsoft.co mwrote in message

When do I need to use AndAlso vs And?

[aaron.kempf@gmail.com]

Re: When to use AndAlso vs And ?

you still don't understand the point.

unnecessary change isn't good.

it is unnecessary

-Aaron


Chris Dunaway wrote:

aaron.kempf@gma il.com wrote:

what a load of crap it worked well enough in VB6

>
Really? How would VB6 handle this code if the instance were null?
>
If (Not obj Is Nothing) And (obj.Property = "something" ) Then
'Do something here
End If
>
It would have crashed because IIRC, And was not short circuited in VB6
. Using AndAlso avoids this in VB.Net.
>

unnecessary change isn't good.
it's unnecessary

>
The original VB.Net beta proposed adding two new operators called
BitAnd and BitOr which would be used for bitwise operations and
changing And and Or to only be logical operations. That would have
been an unnecessary change and, thankfully, they changed it back.
>

>
"Rich" <Rich@discussio ns.microsoft.co mwrote in message

When do I need to use AndAlso vs And?

[Stephany Young]

Re: When to use AndAlso vs And ?

While I concur with the 'use AndAlso and OrElse when doing logical
comparisons' rule of thumb, as usual there are always exceptions to the
rule.

One such exception is the situation where one has 2 functions where both
return a boolean, both execute some code that is critical to the application
and the result of both must be True for some other action to be taken, e.g.:

Private Sub Form_Load(...) Handles MyBase.Load

If FunctionA() And FunctionB() Then
' Take some critical action before continuing
End If

End Sub

Private Function FunctionA() As Boolean

Try
' Some critical code here
Return True
Catch
Return False
End Try

End Function

Private Function FunctionB() As Boolean

Try
' Some other critical code here
Return True
Catch
Return False
End Try

End Function

If AndAlso was used in this case, and FunctionA returned False then
FunctionB would not be called and a critical step would be 'missed'.

I am not advocation that this is a good way to go about things, merely that
it demonstrates a situation where 'short-circuiting' is not desirable.


"Chris Dunaway" <dunawayc@gmail .comwrote in message
news:1167323721 .791014.145250@ n51g2000cwc.goo glegroups.com.. .

Rich wrote:
>

>>
>When do I need to use AndAlso vs And?
>>

>
RobinS explained how those keywords work so I won't repeat that
information. My recommendation is to ALWAYS use AndAlso and OrElse
when doing logical comparisons. It costs you nothing to use them and
you get the benefits of short circuiting.
>
Use And and Or for bitwise operations.
>
The exception being if you are reusing code from VB6 and it might not
be worth the time to change the And's and Or's to AndAlso and OrElse.
>
Chris
>

[aaron.kempf@gmail.com]

Re: When to use AndAlso vs And ?

what a load of crap it worked well enough in VB6

unnecessary change isn't good.
it's unnecessary




Stephany Young wrote:

While I concur with the 'use AndAlso and OrElse when doing logical
comparisons' rule of thumb, as usual there are always exceptions to the
rule.
>
One such exception is the situation where one has 2 functions where both
return a boolean, both execute some code that is critical to the application
and the result of both must be True for some other action to be taken, e.g.:
>
Private Sub Form_Load(...) Handles MyBase.Load
>
If FunctionA() And FunctionB() Then
' Take some critical action before continuing
End If
>
End Sub
>
Private Function FunctionA() As Boolean
>
Try
' Some critical code here
Return True
Catch
Return False
End Try
>
End Function
>
Private Function FunctionB() As Boolean
>
Try
' Some other critical code here
Return True
Catch
Return False
End Try
>
End Function
>
If AndAlso was used in this case, and FunctionA returned False then
FunctionB would not be called and a critical step would be 'missed'.
>
I am not advocation that this is a good way to go about things, merely that
it demonstrates a situation where 'short-circuiting' is not desirable.
>
>
"Chris Dunaway" <dunawayc@gmail .comwrote in message
news:1167323721 .791014.145250@ n51g2000cwc.goo glegroups.com.. .

Rich wrote:

>
When do I need to use AndAlso vs And?
>

RobinS explained how those keywords work so I won't repeat that
information. My recommendation is to ALWAYS use AndAlso and OrElse
when doing logical comparisons. It costs you nothing to use them and
you get the benefits of short circuiting.

Use And and Or for bitwise operations.

The exception being if you are reusing code from VB6 and it might not
be worth the time to change the And's and Or's to AndAlso and OrElse.

Chris

[Chris Dunaway]

Re: When to use AndAlso vs And ?

aaron.kempf@gma il.com wrote:

you still don't understand the point.
>
unnecessary change isn't good.
>
it is unnecessary

I do understand the point, and I agree that unnecessary change isn't
good.

And and Or STILL function like they did before!!

Nothing has changed, a feature has been ADDED.

Chris

[lord.zoltar@gmail.com]

Re: When to use AndAlso vs And ?


aaron.kempf@gma il.com wrote:

what a load of crap it worked well enough in VB6
>
unnecessary change isn't good.
it's unnecessary
>

Ok so maybe change just for the sake of change is sometimes a Bad
Thing, but I don't see a problem with having short-ciruit logic
operators. It's not as if they are the ONLY logic operator, you can
still use "And" and "Or".

[aaron.kempf@gmail.com]

Re: When to use AndAlso vs And ?

it's not a feature.. it's a point of confusion

VB.net has NO TANGIBLE BENEFITS over VB6.
the IDE sucks; it is slower it is more difficult; it doesn't produce
portable code.

I used to be able to write VB6 code, cut and paste it into Notepad and
run it as a VBS file.

When VB.net comes 90% close to being able to have this sort of
simplicity- is when I lower myself to using VB 2005.

and the point of the matter is that it's not called VB.net 2005; it is
merely called VB 2005.

Why are we posting in a newsgroup named DOTNET when we're not talking
about a product named DOTNET?

why are there 40 dead newsgroups at microsoft.publi c.vb?

why did they bother changing the newsgroup name?

-Aaron


Chris Dunaway wrote:

aaron.kempf@gma il.com wrote:

you still don't understand the point.

unnecessary change isn't good.

it is unnecessary

>
I do understand the point, and I agree that unnecessary change isn't
good.
>
And and Or STILL function like they did before!!
>
Nothing has changed, a feature has been ADDED.
>
Chris

[Bruce W. Darby]

Re: When to use AndAlso vs And ?

But Chris,

If you use logic in this way, he can't continue to rail against the machine,
tossing his little tantrums because he needs to change his way of thinking
and coding

Bruce

"Chris Dunaway" <dunawayc@gmail .comwrote in message
news:1167343324 .620302.74580@7 3g2000cwn.googl egroups.com...

aaron.kempf@gma il.com wrote:

>you still don't understand the point.
>>
>unnecessary change isn't good.
>>
>it is unnecessary

>
I do understand the point, and I agree that unnecessary change isn't
good.
>
And and Or STILL function like they did before!!
>
Nothing has changed, a feature has been ADDED.
>
Chris
>

[mg]

Re: When to use AndAlso vs And ?


aaron.kempf@gma il.com wrote:

what a load of crap it worked well enough in VB6
>
unnecessary change isn't good.
it's unnecessary

yawn. If this is the limits of your contribution, don't bother MB.