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I encounter weird exceptions while developping Asp.Net Mvc 5 using Entity Framework 6.0 database-first to access data.

First, when I try to delete a record, a DbUpdateException is thrown on SaveChanges : 

The DELETE statement conflicted with the REFERENCE constraint "ForeignKeyName". 
(...)
The statement has been terminated.

This exception is then caught by our ExceptionFilter :

public void OnException(ExceptionContext filterContext)
{
    // Opening popup
    filterContext.ExceptionHandled = true;
}

Up to now, everything is fine. However, if after that the SavesChanges method is called again to update another entity, the same exception keeps throwing.

I taught it was related to the debug mode (cf post Exception seems to be thrown repeatedly when debugging) but I've the same issue in release.

Any help would be appreciated.

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Francois Stock
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1 Answers1

2

You are probably reusing the same DbContext instance after the delete exception is thrown. If SaveChanges() fails, the changes are still being tracked by the DbContext.ChangeTracker. You have to create a new DbContext instance or clear the change tracker.

Augusto Barreto
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    Or Rollback the changes made to your context –  Feb 02 '15 at 21:33
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    I've chosen the 2d option and wrote a rollback method (cf. [Undo changes in entity framework entities](http://stackoverflow.com/questions/5466677/undo-changes-in-entity-framework-entities)). Thanks, I didn't realize I would have to clear entity after handling the exception. – Francois Stock Feb 03 '15 at 09:28