DataGridView and Deleting Rows
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Hi, I have a DataGridView control on a POS application I am writing as a project. I am having issues when trying to remove certain items from the control. Below is an example :- 1 Item 1 $5.00 -Extra 1 -Extra 2 1 Item 2 $10.00 1 Item 3 $2.00 -Extra 1 I want the user to be able to click on an item (or extra) in the datagridview and delete it. I can do this for single items and extras and it works perfectly (using removeat)but when I select an item, I want to check if there are any "extras" associated with the item and remove them aswell. Extras are always immediately below the item in question. My stumbling point seems to be when I remove 1 using RemoveAt, the index numbers change and I get exceptions. This datagridview is not bound to any datasource and I am creating it on the fly. Any help with the logic would be muchly appreciated. Thanks, Daniel.
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Hi, I have a DataGridView control on a POS application I am writing as a project. I am having issues when trying to remove certain items from the control. Below is an example :- 1 Item 1 $5.00 -Extra 1 -Extra 2 1 Item 2 $10.00 1 Item 3 $2.00 -Extra 1 I want the user to be able to click on an item (or extra) in the datagridview and delete it. I can do this for single items and extras and it works perfectly (using removeat)but when I select an item, I want to check if there are any "extras" associated with the item and remove them aswell. Extras are always immediately below the item in question. My stumbling point seems to be when I remove 1 using RemoveAt, the index numbers change and I get exceptions. This datagridview is not bound to any datasource and I am creating it on the fly. Any help with the logic would be muchly appreciated. Thanks, Daniel.
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Hi, I have a DataGridView control on a POS application I am writing as a project. I am having issues when trying to remove certain items from the control. Below is an example :- 1 Item 1 $5.00 -Extra 1 -Extra 2 1 Item 2 $10.00 1 Item 3 $2.00 -Extra 1 I want the user to be able to click on an item (or extra) in the datagridview and delete it. I can do this for single items and extras and it works perfectly (using removeat)but when I select an item, I want to check if there are any "extras" associated with the item and remove them aswell. Extras are always immediately below the item in question. My stumbling point seems to be when I remove 1 using RemoveAt, the index numbers change and I get exceptions. This datagridview is not bound to any datasource and I am creating it on the fly. Any help with the logic would be muchly appreciated. Thanks, Daniel.
When you delete an item in a list, any list, the indexes of the remaining items may change. There are two easy ways to cope with that: 1. not moving at all: assuming a range of items may have to be deleted, if the first item the be deleted is at index x, use RemoveAt(x); and continue testing for more removals at the same index x, as each removal there will decrement the index of all the # subsequent items by one. 2. working backwards: first determine the range to be deleted, without actually deleting anything; then delete from high index to low index; this also works when the items of interest aren't consecutive. Beware, whatever you choose to do, a
foreachwill fail as an enumerator becomes invalid (and will throw an exception) when the collection gets modified. :)Luc Pattyn [Forum Guidelines] [Why QA sucks] [My Articles]
If you want my opinion or comment, ask in a forum or on my profile page; I will not participate in frackin' Q&A