find a location for property in a new city

Tuesday, 27 July 2010

The specified value is not an instance of type 'Edm.Int64' Parameter name: value. When inserting an object with Entity Framework

When trying to insert an object into my entity data model (i.e. myObjectContext.SaveChanges()) using Entity Framework 4, I got the most confusing error that said "The specified value is not an instance of type 'Edm.Int64' Parameter name: value".

What made it more confusing was that another repository that uses the same entity data model inserted fine. What made it even more confusing was that if I went back to the page that displays the inserted items they were in fact there no matter how many times I refreshed. What made it even more confusing was that they weren't actually in the database!

Mysterious solution

Beware: you won't leave this blog feeling enlightened. What I did worked but made no sense but fixed it:

Given that there is clearly some sort of caching happening I decided to refresh the Application pool for my application. This cleared out all those phantom items that existed on the page but not in the database. Cool...

Then I tried to insert a new item again for a laugh. It worked! It seemed as though recycling the app pools (AKA giving the server a kick up the arse) suddenly made it start working again.

Step 2: Back away slowly from the code and hope it doesn't happen again.

Update: Concrete solution

The problem was I am using Spring.NET for dependency injection and by default it is set to make the references singletons. So I had to change
<object name="MyRepository" type="MyAssembly.MyNamespace.MyRepository, MyAssembly"/>
<object name="MyRepository" type="MyAssembly.MyNamespace.MyRepository, MyAssembly" singleton="false"/>
and it all now works as expected.

Follow britishdev on Twitter

1 comment:

  1. Great Article
    Cloud Computing Projects

    Networking Projects

    Final Year

    Projects for CSE

    JavaScript Training in Chennai


    Training in Chennai

    The Angular Training covers a wide range of topics including Components, Angular Directives, Angular Services, Pipes, security fundamentals,

    Routing, and Angular programmability. The new Angular TRaining will lay the foundation you need to specialise in Single Page Application developer.

    Angular Training