entity framework - The type was not mapped -

im trying run simple program according tutorial find. test code:

program.cs:

using system; using system.collections.generic; using system.data.entity; using system.linq; using system.text; using system.threading.tasks;  namespace ef5withmysqlcodefirst {     class program     {         static void main(string[] args)         {             using(var context = new databasecontext())             {                 var defaultforum = new forum { forumid = 1, name = "default", description="default forum test insertion." };                 context.forums.add(defaultforum);                 context.savechanges();             }             console.readkey();         }          public class forum         {             public int forumid { get; set; }             public string name { get; set; }             public string description { get; set; }         }          public class databasecontext : dbcontext         {             public dbset<forum> forums { get; set; }         }     } } 

this web.config:

<?xml version="1.0" encoding="utf-8"?> <configuration>   <configsections>     <!-- more information on entity framework configuration, visit http://go.microsoft.com/fwlink/?linkid=237468 -->     <section name="entityframework"               type="system.data.entity.internal.configfile.entityframeworksection, entityframework, version=5.0.0.0, culture=neutral, publickeytoken=b77a5c561934e089"              requirepermission="false" />   </configsections>   <startup>     <supportedruntime version="v4.0"                        sku=".netframework,version=v4.5" />   </startup>   <entityframework>     <defaultconnectionfactory type="system.data.entity.infrastructure.localdbconnectionfactory, entityframework">       <parameters>         <parameter value="v11.0" />       </parameters>     </defaultconnectionfactory>   </entityframework> </configuration> 

when execute code, in using(var context = new databasecontext()) line, following error:

the type 'ef5withmysqlcodefirst.program+forum' not mapped. check type has not been explicitly excluded using ignore method or notmappedattribute data annotation. verify type defined class, not primitive, nested or generic, , not inherit entityobject.

please ignore name mysql since not trying yet connect mysql work localdb. searched around , can't solution problem yet.

i think it's failing because forum class nested inside program class. error message says, entity types can't nested. try moving outside it's top-level class within namespace.