CollectionBase problem

  • Thread starter Thread starter Guest
  • Start date Start date
G

Guest

Hi,

i have a windows application.

This application uses a object that its of type collectionbase.

For other hand i have a ListBox, and i use this collection to fill it.

I have implemented the methods (in my class that derives from collection
base):

//to get an element from collection
public type of object Get_(int index)
{
return (type of object) List[index]
}
//to add into collection
public void Add_(type of the object object)
{
List.Add(object)
}
//to remove from collection
public void Remove_(type of the object object)
{
List.Remove(object)
}
I dont know if my steps are correctly:

1) when application loads i fill the collection, and i fill the listbox with
the collection.
2) When a person clicks in a item i get the object from the collection with
the index (ListBox.SelectedIndex)
3) i remove from collection this object that i got in the step 2.
4) i assign the datasource of the listbox to null
5) i remove from the listbox the item selected
6) i assign the datasource of the listbox the collection (with the item
removed in step 3)

When i execute the application, and i delete an item, all goes correctly
except when i delete the last.... In this case (deleting the last item) the
application deletes it, but when i selected another item, i get an Error of
type IndexOutOfRange exception....

Questions:
1) What could be the problem?
2) Its my logic to do this wrong?
3) Generally this kind of stuff are made following this way?

Any advice would be appreciated...
 
When i execute the application, and i delete an item, all goes correctly
except when i delete the last.... In this case (deleting the last item)
the
application deletes it, but when i selected another item, i get an Error
of
type IndexOutOfRange exception....
Click to expand...

How is this possible?
If you delete the last item, how can you select another item?
There's nothing to select...
 
Hi Dan,

Thanks for you early response, and sorry for my bad explanation...

My problem is, I select a item from ListBox, then delete from database
the ID of the Item in database, then i delete the selectedindex from
collection of objects, and then i clear the items from the listbox and i
assign again the datasource to the collection (with the object
removed)...

Why doesnt work if i select the last item?

Thanks and sorry for my last bad explanation....
 
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