Problem looping through listbox to delete item

[VB Programmer]

Here's the code:
For Each li As ListItem In Me.lstAssignedEmailAddresses.Items
If li.Selected = True Then
Me.lstAssignedEmailAddresses.Items.Remove(li)
End If
Next

When I remove an item I get this error:
System.InvalidOperationException: Collection was modified; enumeration
operation may not execute. at
System.Collections.ArrayListEnumeratorSimple.MoveNext()

I think its because I'm changing the collection while trying to loop through
it.

Any ideas for a workaround?

Thanks.

 

[Ben Lucas]

That's correct. You cannot change a collection while you are looping
through it.

However, a simple change can allow you to do this:

dim alItemsToDelete as ArrayList = new ArrayList()
For Each li As ListItem In Me.lstAssignedEmailAddresses.Items
If li.Selected = True Then
alItemsToDelete.Add(li)
Me.lstAssignedEmailAddresses.Items.Remove(li)
End If
Next
For Each li as ListItem In alItemsToDelete
Me.lstAssignedEmailAddresses.Items.Remove(li)
Next

Hope this helps

Ben Lucas
Lead Developer
Solien Technology, Inc.
www.solien.com

 

[VB Programmer]

Thanks!

That's correct. You cannot change a collection while you are looping
through it.

However, a simple change can allow you to do this:

dim alItemsToDelete as ArrayList = new ArrayList()
For Each li As ListItem In Me.lstAssignedEmailAddresses.Items
If li.Selected = True Then
alItemsToDelete.Add(li)
Me.lstAssignedEmailAddresses.Items.Remove(li)
End If
Next
For Each li as ListItem In alItemsToDelete
Me.lstAssignedEmailAddresses.Items.Remove(li)
Next

Hope this helps

Ben Lucas
Lead Developer
Solien Technology, Inc.
www.solien.com

 

[Marina]

As someone else said, you can't modify a collection while looping through
it.

However, if you don't use an enumerator, but just use a regular for loop,
that will work fine.