IIF with Array

[Shawn]

OK, Please tell me if I am doing something wrong here...

This does NOT work if args.Length = 0 (It gives an
IndexOutOfRange Exception on the args() array)
Public Shared Sub Main(ByVal args() As String)
Dim val As String = IIf(args.Length 0, args(0).ToStrin g,
"10")
Console.WriteLi ne("Waiting for workflow completion ({0}
seconds...).", val)
End Sub

This DOES work if args.Length = 0
Public Shared Sub Main(ByVal args() As String)
Dim val As String
If args.Length 0 Then
val = args(0)
Else
val = "10"
End If
Console.WriteLi ne("Waiting for workflow completion ({0}
seconds...).", val)
End Sub

Am I wrong to assume that IIF can be used this way?

Thanks,
Shawn

[Stephany Young]

Re: IIF with Array

Yes!

To use IIf, both the TruePart and the FalsePart MUST be evaluatable.

In the case of args.Length = 0 then args(0).ToStrin g cannot be evaluated
because the array, (args), does not have any elements. IIf thefore,
correctly, throws an exception.

And, yes, (before anyone jumps down my throat), I did read that VB.Net 2008
has a 'proper' ternary operator.


"Shawn" <shawngentry@gm ail.comwrote in message
news:a11ada30-f5c3-4ff2-8395-76e8cbc0423d@d2 1g2000prf.googl egroups.com...

OK, Please tell me if I am doing something wrong here...
>
This does NOT work if args.Length = 0 (It gives an
IndexOutOfRange Exception on the args() array)
Public Shared Sub Main(ByVal args() As String)
Dim val As String = IIf(args.Length 0, args(0).ToStrin g,
"10")
Console.WriteLi ne("Waiting for workflow completion ({0}
seconds...).", val)
End Sub
>
This DOES work if args.Length = 0
Public Shared Sub Main(ByVal args() As String)
Dim val As String
If args.Length 0 Then
val = args(0)
Else
val = "10"
End If
Console.WriteLi ne("Waiting for workflow completion ({0}
seconds...).", val)
End Sub
>
Am I wrong to assume that IIF can be used this way?
>
Thanks,
Shawn

[Cor Ligthert[MVP]]

OT: Re: IIF with Array

You apparently are not using STRICT ON. I strongly urge you to. It
makes you use some casts, but you can find a lot of bugs with it on.

Yea, I don't understand why Armin never points people on this.

(You have to be a very long time regular from this newsgroup to understand
the meaning from what I wrote)

:-)

Cor

[Cor Ligthert[MVP]]

Re: IIF with Array

>

And, yes, (before anyone jumps down my throat), I did read that VB.Net
2008 has a 'proper' ternary operator.
>
>

However a ternary operator stays in my idea something that is hard to
understand by maintaining and therefore in my idea more meant for scripting;
Where that is standard difficult.

Cor

[Michael C]

Re: IIF with Array

"Cor Ligthert[MVP]" <notmyfirstname @planet.nlwrote in message
news:03114FD1-C11F-4AFD-89C5-48927C91C8AD@mi crosoft.com...

>And, yes, (before anyone jumps down my throat), I did read that VB.Net
>2008 has a 'proper' ternary operator.
>>
>>

However a ternary operator stays in my idea something that is hard to
understand by maintaining and therefore in my idea more meant for
scripting; Where that is standard difficult.

As long as it's kept simple I don't see the problem:

int x = (SomeCheck ? 1 : 0)

Surely not too hard to maintain?

Michael

[Stephany Young]

Re: IIF with Array

What's to understand?

If one understands the concept of If ... Then ... Else then one already
understands the concept of a ternary operator.


"Cor Ligthert[MVP]" <notmyfirstname @planet.nlwrote in message
news:03114FD1-C11F-4AFD-89C5-48927C91C8AD@mi crosoft.com...

>And, yes, (before anyone jumps down my throat), I did read that VB.Net
>2008 has a 'proper' ternary operator.
>>
>>

However a ternary operator stays in my idea something that is hard to
understand by maintaining and therefore in my idea more meant for
scripting; Where that is standard difficult.
>
Cor
>
>

[Cor Ligthert [MVP]]

Re: IIF with Array

Michael,

As long as it's kept simple I don't see the problem:
>
int x = (SomeCheck ? 1 : 0)
>
Surely not too hard to maintain?
>

You are rigth

However, now this one and it seems that people to like it for things like
this.

TelBijBonus(Ver koper).Value = (Klant="Brabant " and Provincie <"Gelderland "
And HeeftKabel And HeeftBetaald ? BerekenWinst :
BerekenAanmanin g.ResultaatZero )

I don't know it it is syntyntical complete however you understand probably
what I mean?

:-)

Cor

[Cor Ligthert [MVP]]

Re: IIF with Array

If one understands the concept of If ... Then ... Else then one already
understands the concept of a ternary operator.
>

Try to find out what I did mean with my piece of sample code to Michael,

When nicely done with an if then this is easy to read for me, this one I
made is something I have to put in pieces first.

However maybe it is me.


Cor

[Michael C]

Re: IIF with Array

"Cor Ligthert [MVP]" <notmyfirstname @planet.nlwrote in message
news:utJ6G3mNIH A.748@TK2MSFTNG P04.phx.gbl...

You are rigth
>
However, now this one and it seems that people to like it for things like
this.
>
TelBijBonus(Ver koper).Value = (Klant="Brabant " and Provincie <>
"Gelderland " And HeeftKabel And HeeftBetaald ? BerekenWinst :
BerekenAanmanin g.ResultaatZero )
>
I don't know it it is syntyntical complete however you understand probably
what I mean?

I've seen this arguement raised before. Just because something can be abused
does not mean that it will be abused and should therefore be removed. Pretty
much everything can be abused, even the standard if statement.

Michael

[Jay B. Harlow [MVP - Outlook]]

Re: IIF with Array

Shawn,
As the others have pointed out, IIf is a function; all arguments will be
evaluated, prior to VB 2008 I would use a generic IIf to get around the
casting problem.

http://www.tsbradley.net/Cookbook/Generics/genericIIf.aspx

Starting with VB 2008 I now use the If operator.

Dim val As String = If(args.Length 0, args(0).ToStrin g, "10")

There are two versions of the If operator. The 3 argument version above that
replaces the IIf, and a 2 argument version similar to IsNull in SQL Server.

http://msdn2.microsoft.com/en-us/lib...85(VS.90).aspx

NOTE: You can introduce a Generic IIf that has an Obsolete attribute

<Obsolete_
Public Function IIf(Of T)(ByVal expression As Boolean, _
ByVal truePart As T, ByVal falsePart As T) As T
If expression Then
Return truePart
Else
Return falsePart
End If
End Function

Which will highlight every place your using the function allowing you to
change over to the operator.

--
Hope this helps
Jay B. Harlow [MVP - Outlook]
..NET Application Architect, Enthusiast, & Evangelist
T.S. Bradley - http://www.tsbradley.net


"Shawn" <shawngentry@gm ail.comwrote in message
news:a11ada30-f5c3-4ff2-8395-76e8cbc0423d@d2 1g2000prf.googl egroups.com...

OK, Please tell me if I am doing something wrong here...
>
This does NOT work if args.Length = 0 (It gives an
IndexOutOfRange Exception on the args() array)
Public Shared Sub Main(ByVal args() As String)
Dim val As String = IIf(args.Length 0, args(0).ToStrin g,
"10")
Console.WriteLi ne("Waiting for workflow completion ({0}
seconds...).", val)
End Sub
>
This DOES work if args.Length = 0
Public Shared Sub Main(ByVal args() As String)
Dim val As String
If args.Length 0 Then
val = args(0)
Else
val = "10"
End If
Console.WriteLi ne("Waiting for workflow completion ({0}
seconds...).", val)
End Sub
>
Am I wrong to assume that IIF can be used this way?
>
Thanks,
Shawn