C# representation of VB.net "OrElse" operator?

  • Thread starter Thread starter Rich P
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Rich P

VB.net:
If this Or that Then...

C#
if (this || that){...}

VB.net If this OrElse that Then

C#
if (this .....?

I believe in VB.Net OrElse wont evaluate the next expression unless the
first expression is completely false where with OR both expressions get
evaluated - I think - I never get this part straight. Does C# have an
equivalent to OrElse? Or is it just a straight forward || for
everything that is Or/OrElse related?


Rich
 
VB.net:
If this Or that Then...

C#
if (this || that){...}

VB.net If this OrElse that Then

C#
if (this .....?

I believe in VB.Net OrElse wont evaluate the next expression unless the
first expression is completely false where with OR both expressions get
evaluated - I think - I never get this part straight. Does C# have an
equivalent to OrElse? Or is it just a straight forward || for
everything that is Or/OrElse related?
Click to expand...

|| = OrElse. C# has NO equivalent to VB's OR statement as far as logical
comparisons go. In other words, you can't make C# NOT short-circuit. To do
so would require multiple if statements.

Bitwise, VB's OR = C#'s |.
 
|| = OrElse. C# has NO equivalent to VB's OR statement as far as logical
comparisons go. In other words, you can't make C# NOT short-circuit. To do
so would require multiple if statements.

Bitwise, VB's OR = C#'s |.
Click to expand...

I should expound. Normally you ALWAYS want short-circuiting. The only time
you wouldn't would be if the conditional had side effects and you wanted to
be sure to trigger those side effects for all conditionals. I think most
folks in this group would say that it's a bad idea to put all that into an
if statement and would instead recommend that you execute the functions to
produce those side effects first and capture the results, thne make your
conditional test the results.

In other words, I can't imagine why anyone would try to duplicate VB's
logical OR behavior. It was dumb to begin with (and this is coming from a VB
guy!) and I was thrilled to see VB "grow up" and FINALLY get a
short-circuiting operator. The few times I write in VB.NET (2005+) I always
use OrElse.
 
I should expound. Normally you ALWAYS want short-circuiting. The only time
you wouldn't would be if the conditional had side effects and you wanted to
be sure to trigger those side effects for all conditionals. I think most
folks in this group would say that it's a bad idea to put all that into an
if statement and would instead recommend that you execute the functions to
produce those side effects first and capture the results, thne make your
conditional test the results.

In other words, I can't imagine why anyone would try to duplicate VB's
logical OR behavior. It was dumb to begin with (and this is coming from aVB
guy!) and I was thrilled to see VB "grow up" and FINALLY get a
short-circuiting operator. The few times I write in VB.NET (2005+) I always
use OrElse.
Click to expand...

Yes, it was fun when i switched my code from C# to VB.Net First Time.

if ( someStringObject != null && someStringObject.Length > 0)

NullReferenceException bada :)
if someStringObject is nothing and someStringObject.Length = 0 then

end if
 
if ( someStringObject != null && someStringObject.Length > 0)

NullReferenceException bada :)
if someStringObject is nothing and someStringObject.Length = 0 then

end if- Dölj citerad text -

- Visa citerad text -
Click to expand...

You did that or the "helper", havent tried anything C# but VB6->VB.NET
and it went ... lets just say it stays in VB6 for a while... still
cant sleep after the first chock... ;)

//CY
 
Rich P said:
VB.net:
If this Or that Then...

C#
if (this || that){...}

VB.net If this OrElse that Then

C#
if (this .....?

I believe in VB.Net OrElse wont evaluate the next expression unless the
first expression is completely false where with OR both expressions get
evaluated - I think - I never get this part straight. Does C# have an
equivalent to OrElse? Or is it just a straight forward || for
everything that is Or/OrElse related?


Rich
Click to expand...


One bar tests both sides of the conditional, while two bars skips out if the
first is true.
 
One bar tests both sides of the conditional, while two bars skips out if
the first is true.
Click to expand...

Hmmm, now that I think about it, that WILL work, but I guess since I see " |
" as purely a bitwise operator I didn't consider this route. But won't the
compiler throw a warning? Ultimately, you normally SHOULDN'T do this, even
if you CAN....
 
Jeff Johnson said:
Hmmm, now that I think about it, that WILL work, but I guess since I see "
| " as purely a bitwise operator I didn't consider this route. But won't
the compiler throw a warning? Ultimately, you normally SHOULDN'T do this,
even if you CAN....
Click to expand...


No, they are specifically allowed in the language (one bar, I mean).
& and && are also both defined for conditionals, but that is another
question...
 
Jeff said:
|| = OrElse. C# has NO equivalent to VB's OR statement as far as logical
comparisons go. In other words, you can't make C# NOT short-circuit. To do
so would require multiple if statements.
Click to expand...

That's not correct. The | operator does that.

It's not very well known, and rarely used. Although I have known about
it for quite some time, I never had any use for it until a few days ago...
Bitwise, VB's OR = C#'s |.
Click to expand...

Only for integer operands.
 
That's not correct. The | operator does that.

It's not very well known, and rarely used. Although I have known about it
for quite some time, I never had any use for it until a few days ago...
Click to expand...

So then this is a case where C# differs from C, right? Because I'm pretty
sure a C compiler would complain (warning) if it thought you used | when you
meant ||.
 
Jeff said:
So then this is a case where C# differs from C, right? Because I'm pretty
sure a C compiler would complain (warning) if it thought you used | when you
meant ||.
Click to expand...

Yes, in C the | and & operators are only binary operators, they are not
defined for logical operands. That makes a bit of sense, it would be
rather a mess as C has implicit conversion between integers and boolean.

How C# distinguishes between types is actually more like Pascal (Delphi)
than C.
 
Family said:
No, they are specifically allowed in the language (one bar, I mean).
Click to expand...

Which is to say that the language defines "||" as nothing more than "the
short-circuiting version of |"
 
Göran Andersson said:
Yes, in C the | and & operators are only binary operators, they are not
defined for logical operands. That makes a bit of sense, it would be
rather a mess as C has implicit conversion between integers and boolean.
Click to expand...

Actually, no. In C the result of the bitwise operation is compared to
zero, and if not equal it's considered true.

(Well, it might give a warning depending upon the specific compiler and
it's settings but it'd work).
 
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