I need a little help here.

[Carlos Yakimov]

I want to convert this C# Linq Query into VB.NET

void Load() {
int i = 1;
var q = from P in Persons
select new System.Windows. Forms.ListViewI tem( P.Name, i++ );
}

I did this:

Sub Load()
Dim I As Integer = 1
Dim q = from P in Persons _
Select New ListViewItem(P. Name, i++
? )
End Sub

My problem is how I can use the ++ Operator in Vb?

Thanks in advance.

[Tom Dacon]

Re: I need a little help here.

Carlos, the ++ operator in C# uses the current value, if it's involved in an
expression of any kind, and then increments it after use. So in the C# code,
it will use the i value of 1 as an argument in the select, and then will set
it to 2 afterwards.

So the equivalent in VB.Net would be:

Sub Load()

Dim i As Integer = 1

Dim q = from P in Persons _
Select New ListViewItem(P. Name, i)
i += 1

' Other code follows, presumably...

End Sub


Tom Dacon
Dacon Software Consulting


"Carlos Yakimov" <masterkid@cant v.netwrote in message
news:uRLWBmanIH A.3940@TK2MSFTN GP05.phx.gbl...

>I want to convert this C# Linq Query into VB.NET
>
void Load() {
int i = 1;
var q = from P in Persons
select new System.Windows. Forms.ListViewI tem( P.Name,
i++ );
}
>
I did this:
>
Sub Load()
Dim I As Integer = 1
Dim q = from P in Persons _
Select New ListViewItem(P. Name, i++
? )
End Sub
>
My problem is how I can use the ++ Operator in Vb?
>
Thanks in advance.

[Lloyd Sheen]

Re: I need a little help here.


"Tom Dacon" <tdacon@communi ty.nospamwrote in message
news:uHGgNkbnIH A.5280@TK2MSFTN GP02.phx.gbl...

Carlos, the ++ operator in C# uses the current value, if it's involved in
an expression of any kind, and then increments it after use. So in the C#
code, it will use the i value of 1 as an argument in the select, and then
will set it to 2 afterwards.
>
So the equivalent in VB.Net would be:
>
Sub Load()
>
Dim i As Integer = 1
>
Dim q = from P in Persons _
Select New ListViewItem(P. Name, i)
i += 1
>
' Other code follows, presumably...
>
End Sub
>
>
Tom Dacon
Dacon Software Consulting
>
>
"Carlos Yakimov" <masterkid@cant v.netwrote in message
news:uRLWBmanIH A.3940@TK2MSFTN GP05.phx.gbl...

>>I want to convert this C# Linq Query into VB.NET
>>
>void Load() {
> int i = 1;
> var q = from P in Persons
> select new System.Windows. Forms.ListViewI tem( P.Name,
>i++ );
>}
>>
>I did this:
>>
>Sub Load()
>Dim I As Integer = 1
>Dim q = from P in Persons _
> Select New ListViewItem(P. Name,
>i++ ? )
>End Sub
>>
>My problem is how I can use the ++ Operator in Vb?
>>
>Thanks in advance.

>
>

I tried this and the C# version would provide an incremented value for each
listviewitem created. So you would expect a collection of listviewitems
where the imageIndex would start at 1 and increment for each item.

When you try the code in VB (and I have no idea why) you end up with a list
of listviewitems and each has an imageIndex of 2. If I change the code to i
+=2 then the items have an imageIndex of 3. It seems that the final
increment is what is used as if the value is not created until used.

LS

[Lloyd Sheen]

Re: I need a little help here.


"Lloyd Sheen" <a@b.cwrote in message
news:OnmUzPcnIH A.4292@TK2MSFTN GP04.phx.gbl...

>
"Tom Dacon" <tdacon@communi ty.nospamwrote in message
news:uHGgNkbnIH A.5280@TK2MSFTN GP02.phx.gbl...

>Carlos, the ++ operator in C# uses the current value, if it's involved in
>an expression of any kind, and then increments it after use. So in the C#
>code, it will use the i value of 1 as an argument in the select, and then
>will set it to 2 afterwards.
>>
>So the equivalent in VB.Net would be:
>>
>Sub Load()
>>
> Dim i As Integer = 1
>>
> Dim q = from P in Persons _
> Select New ListViewItem(P. Name, i)
> i += 1
>>
> ' Other code follows, presumably...
>>
>End Sub
>>
>>
>Tom Dacon
>Dacon Software Consulting
>>
>>
>"Carlos Yakimov" <masterkid@cant v.netwrote in message
>news:uRLWBmanI HA.3940@TK2MSFT NGP05.phx.gbl.. .

>>>I want to convert this C# Linq Query into VB.NET
>>>
>>void Load() {
>> int i = 1;
>> var q = from P in Persons
>> select new System.Windows. Forms.ListViewI tem( P.Name,
>>i++ );
>>}
>>>
>>I did this:
>>>
>>Sub Load()
>>Dim I As Integer = 1
>>Dim q = from P in Persons _
>> Select New ListViewItem(P. Name,
>>i++ ? )
>>End Sub
>>>
>>My problem is how I can use the ++ Operator in Vb?
>>>
>>Thanks in advance.

>>
>>

>
I tried this and the C# version would provide an incremented value for
each listviewitem created. So you would expect a collection of
listviewitems where the imageIndex would start at 1 and increment for each
item.
>
When you try the code in VB (and I have no idea why) you end up with a
list of listviewitems and each has an imageIndex of 2. If I change the
code to i +=2 then the items have an imageIndex of 3. It seems that the
final increment is what is used as if the value is not created until used.
>
LS

Ok I think you can use a function to do the incrementing:

Dim Persons() As String = {"Him", "Her", "Them"}


Dim ii As Integer = 0

Private Sub Button1_Click(B yVal sender As System.Object, ByVal e As
System.EventArg s) Handles Button1.Click
Dim tst = From t In Persons _
Select New ListViewItem(t, GiveMeAnInt(t))

Dim i As Integer = tst.Count
Dim tl As List(Of ListViewItem) = tst.ToList
End Sub

Private Function GiveMeAnInt(ByV al tmp As String) As Integer
ii += 1
Return ii
End Function


Once again though the imageIndex values are in fact 4,5,6 which I think
confirms that somehow the values are being put in at a time other than what
I would think is correct. Linq has its values but I don't think that in
the case of VB that this works very well.


Tracing the call to GiveMeAnInt shows 6 calls. Seems like the .ToList
recalls the values so if you want to create the list you would have to put
an ii=0 prior to the .ToList call. My last iteration also removed the need
to have a parameter to the GiveMeAnInt. All in all quite a kludge.

Lloyd Sheen

[Tom Dacon]

Re: I need a little help here.

You know, I just realized that I was completely off base with my suggestion.
I haven't actually used Linq (we're still on 2.0), and I was just thinking
that what I was seeing in the OP's code was a simple function call. Clearly
the constructor's being called once for each hit in the select. So my
suggestion wasn't worth a damn.

Sorry 'bout that.

Tom Dacon