Question

I’m developing a web app using the entity framework. I load a list of objects and bind it to a repeater to show a summary of all the items. The user may click an edit icon or a delete icon for each item in the repeater.

Example:

Item 1 | Edit | Delete

Item 2 | Edit | Delete

…

Editing works fine when using a rowversion column for concurrency because the record is loaded and the values for the ID and rowversion column are persisted in hidden form fields. These “original” values are then available to use later when doing the update.

However, if the user clicks Delete for a record, I load the object from the database, call DeleteObject(), then call SaveChanges(). The problem with this is that when I load the record, it gets the latest rowversion value, so any concurrency checking is rendered useless.

How can I ensure that concurrency checking takes place when deleting a record?

Answer 1

After reading the answer to this question, I decided to use the following approach.

1. Use hidden form fields to store the ID and rowversion value.
2. When the user clicks the delete button, load the object from the database. This object contains a rowversion value that may be different than what is stored in the hidden field.
3. Assign the rowversion value from the hidden field to the appropriate property
   on the object.
4. Call the object state manager’s AcceptChanges() method for this object. This causes the rowversion value that I had stored to be accepted as the “current” value.
5. Delete the object and call SaveChanges() on the object context.

Therefore, the original rowversion value I stored is passed to SQL when attempting to delete the record and is compared to the current value in the row. If they do not match, an OptimisticConcurrencyException is raised.