Collection Question

**Tim Patrick** · Oct 24 '06, 03:55 PM

Re: Collection Question

When using reference types (and probably when using complex value types),
the Remove() method only removes the specific instance of an object. It doesn't
remove an instance that just happens to contain the same member values as
one already in the collection. To remove the specific item, you would first
need to get a reference to the actual instance in the collection, and then
call Remove(), passing it that reference. For instance, the following code
would scan through the list and remove the item you seek.

For Each scanItem As EPCInfoClass In LoadedEPCs
If (scanItem.EPC = "30540232801ADB 0000000006") Then
LoadedEPCs.Remo ve(scanItem)
Exit For
End If
Next scanItem

There are other ways to accomplish this. You could override the Equals method
for the class and use it to locate matching items.

Public Overrides Function Equals(ByVal obj As Object) As Boolean
' ----- Allow IndexOf() and Contains() searches.
If (TypeOf obj Is String) Then
Return CBool(CStr(obj) = Me.EPC)
Else
Return MyBase.Equals(o bj)
End If
End Function

Then you could use a statement like this.

LoadedEPCs.Remo veAt(LoadedEPCs .IndexOf("30540 232801ADB000000 0006"))

-----
Tim Patrick
Start-to-Finish Visual Basic 2005

I have a collection that I add my objects to. When I go to remove an
object
from the collect I get an error {"Cannot remove the specified item
because
it was not found in the specified Collection."}
Now I do understand what it is saying but I know the object is in the
collection.
Here is the code I am using.
>
CurrentEPCInfo. ID = "Kleenex";
>
CurrentEPCInfo. EPC = "30540232801ADB 0000000006";
>
CurrentEPCInfo. PIC = @"C:\Visual Studio
Projects\RFID\K CC.MPAM.RFID.Ro cketCart\KCC.MP AM.RFID.RocketC art\Pics\K
leenexTissue.jp g";
>
CartEPCs.Remove (CurrentEPCInfo );
>
Now what really confuses me is if I do this
>
LoadedEPCs.Add( CurrentEPCInfo) ;
>
LoadedEPCs.Remo ve(CurrentEPCIn fo);
>
Add it and then remove it right away it works.
>
Any idea's?
>
TIA,
Brett

**Brett Wesoloski** · Oct 24 '06, 04:15 PM

Re: Collection Question

Ah, thanks! That makes sense.

"Tim Patrick" <invalid@invali d.com.invalidwr ote in message
news:e3b469760c d98c8c564446a6b c2@newsgroups.c omcast.net...

When using reference types (and probably when using complex value types),
the Remove() method only removes the specific instance of an object. It
doesn't remove an instance that just happens to contain the same member
values as one already in the collection. To remove the specific item, you
would first need to get a reference to the actual instance in the
collection, and then call Remove(), passing it that reference. For
instance, the following code would scan through the list and remove the
item you seek.
>

>For Each scanItem As EPCInfoClass In LoadedEPCs
> If (scanItem.EPC = "30540232801ADB 0000000006") Then
> LoadedEPCs.Remo ve(scanItem)
> Exit For
> End If
>Next scanItem

>
There are other ways to accomplish this. You could override the Equals
method for the class and use it to locate matching items.
>

> Public Overrides Function Equals(ByVal obj As Object) As Boolean
> ' ----- Allow IndexOf() and Contains() searches.
> If (TypeOf obj Is String) Then
> Return CBool(CStr(obj) = Me.EPC)
> Else
> Return MyBase.Equals(o bj)
> End If
> End Function

>
Then you could use a statement like this.
>

>LoadedEPCs.Rem oveAt(LoadedEPC s.IndexOf("3054 0232801ADB00000 00006"))

>
-----
Tim Patrick
Start-to-Finish Visual Basic 2005
>

>I have a collection that I add my objects to. When I go to remove an
>object
>from the collect I get an error {"Cannot remove the specified item
>because
>it was not found in the specified Collection."}
>Now I do understand what it is saying but I know the object is in the
>collection.
>Here is the code I am using.
>>
>CurrentEPCInfo .ID = "Kleenex";
>>
>CurrentEPCInfo .EPC = "30540232801ADB 0000000006";
>>
>CurrentEPCInfo .PIC = @"C:\Visual Studio
>Projects\RFID\ KCC.MPAM.RFID.R ocketCart\KCC.M PAM.RFID.Rocket Cart\Pics\K
>leenexTissue.j pg";
>>
>CartEPCs.Remov e(CurrentEPCInf o);
>>
>Now what really confuses me is if I do this
>>
>LoadedEPCs.Add (CurrentEPCInfo );
>>
>LoadedEPCs.Rem ove(CurrentEPCI nfo);
>>
>Add it and then remove it right away it works.
>>
>Any idea's?
>>
>TIA,
>Brett

>
>

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