Entity Framework Type FixupCollection`1 is not marked as serializable.

Entity Framework Autogenerated Classes Not Marked as Serializable.

This error comes about while trying to Serialize an EntityFramework Entity that has Associations. I got my error after creating a New entity, saving it, then doing Update on the newly created entity.

A workaround is to add the [Serializable] attribute to the FixUpCollection class, which is located in your .cs file. So, if your EF Template is called StudentEnrolment.tt then FixupCollection is located in StudentEnrolment.cs. Make FixupCollection look like this:

[Serializable]
public class FixupCollection : ObservableCollection

The permanent fix is to modify your Entity Framework template file to make sure that every time your template is run and your Entity classes regenerated then the Serializable attribute is plonked on top of the EF FixupCollection class.

So edit your equivalent StudentEnrolments.tt and find the line where FixupCollection is generated and simply insert the text “[Serializable]” above it, exactly as you would in your class definition, like so:


#>
// An System.Collections.ObjectModel.ObservableCollection that raises
// individual item removal notifications on clear and prevents adding duplicates.
[Serializable]
public class FixupCollection : ObservableCollection
{

All credit to marc_s at Stack Overflow who wrote this and Ross Pace who linked to it from here.

Once again for lovers of Stack Dumps, here’s the full error:

Type 'SubstationLoad.Data.Model.FixupCollection`1[[SubstationLoad.Data.Model.Substation, SubstationLoad.Data, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]' in Assembly 'SubstationLoad.Data, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' is not marked as serializable.

Tags: Entity Framework, Serialization