Entity Framework Duplicate type name within an assembly (6.1.0)

Question

I am not sure what is going on but I keep getting the following exception when doing a query. "Duplicate type name within an assembly." I have not been able to find a solution on the web. I had resolved the issue by removing entity framework from all the projects in the solutions and re-installing using nugget. Then all of the sudden the exception is back. I have verified my table schema over and over and find nothing wrong with.

This is the query causing the exception.

    var BaseQuery = from Users in db.Users
            join UserInstalls in db.UserTenantInstalls on Users.ID equals UserInstalls.UserID
            join Installs in db.TenantInstalls on UserInstalls.TenantInstallID equals Installs.ID
            where
                Users.Username == Username
                && Users.Password == Password
                && Installs.Name == Install
            select Users;

    var Query = BaseQuery.Include("UserTenantInstalls.TenantInstall");

    return Query.FirstOrDefault();

As I mentioned previously the same query was working before. The data has not changed and the code has not changed.

Answer 1

As a work around, this only happens if you are single-stepping using the debugger. If you place your break point a few lines further down inside your source, the error will not show up.

I haven't uninstalled, and this at least allows me to continue working.

Answer 2

This is a new issue with EF 6.1.0, and the EF team is aware of the problem:

https://entityframework.codeplex.com/workitem/2228

Answer 3

Faced the same in my WCF webservice recently. Just clean your solution and rebuild it. This should fix the issue.

Answer 4

None of the above seem to work for me however in the link specified earlier i did fin this, which worked for me. This was submitted by 'bunomonteiro'

To Fix "Duplicate type name within an assembly"

I had similar issue. I checked all my models/classes and I have not used duplicate names for types. I deleted the assemblies and regenerated the the model and context object from the database and still had the same issue.

A trace yielded in Visual Studio "Children could not be evaluated". The SOLUTION is to add .ToList(); or ToArray(); or ToDictionary() etc, to your query. etc.

eg. var query = context.TableName.Where(x => x.name =="CodeRealm").ToList();

PingBack - http://entityframework.codeplex.com/workitem/1898

bunomonteiro wrote Jul 18 at 3:37 AM