Deleting last item in DataGridView

Tray posted on Thursday, February 08, 2007

I'm using an EditableRootList and binding it to a DataGridView through a BindingSource.

When I delete the last object in the list using in-place editing, the DataGridView throws an execption stating that 'System.IndexOutOfRangeException: Index 41 does not have a value.'

I'm trying to use the DataError event of the DataGridView control to select the row above the deleted row, but the deleted row stays in the DataGridView with no data in the cells.

How can I get the DataGridView to delete a row in the way that the user expects?

Tray

RockfordLhotka replied on Friday, February 09, 2007

All the objects in the ERLB are returning unique values from GetIdValue()?

Tray replied on Friday, February 09, 2007

Hi Rocky,

The ERBL is called CategoryList.

I have a Category root class with a private mCategoryID as Integer as the Id value. This member is returned as an object in the GetIdValue() method. mCategoryID is an identity field (incremental) updated from the db during Save(). I have not implemented a temporary primary key field in the class as the object is being updated everytime the user moves away from the row, so I gathered that there would not be any conflicts (only 1 new item can exists at a time - it either gets cancelled or accepted before any other operations can be performed).

Any ideas?

Love the framework - brilliant job.

Tray replied on Friday, February 09, 2007

Hi again Rocky,

I decided to try using a SortedBindingList to add some functionality for the user and it fixed my deletion problem. (NB: I got the exception message above for any index in the list - not only the last index.)

Not sure why, but the ERLB doesn't seem to handle the in-place deletion of an object as well as the SortedBindingList does. Any ideas Rocky?

This has now created another problem that I have to investigate:

• I cannot add a new item to the list using in-place editing. SortedBindingList throws an exception (at line 793 in Private Function OriginalIndex(ByVal SortedIndex As Integer) As Integer) stating:
  'Index was out of range. Must be non-negative and less than the size of the collection.
  Parameter name: index'.

I noticed that SortedBindingList does not have an AddNewCore() method for the databinding to call.

Anyway, I'll keep looking around.

If you could point me in the right direction, that would be great

Tray

RockfordLhotka replied on Thursday, February 22, 2007

SortedBindingList is merely a view over another list, so if you want to AllowNew, that source list must handle that by implementing AddNewCore().

RockfordLhotka replied on Thursday, February 22, 2007

To follow on, here's a very simple ERLB bound to a grid - and a SortedBindingList view of that ERLB bound to another grid.

I set up the Root object so its unique id value is assigned by DP_Insert(), so it should be quite comparable to your example. I'm able to add and remove items from the grid without a problem, so I'm wondering if you can look at this and see how it differs from what you are doing?