How to setup a many to many relationship - entity-framework-6

Question

I had to change a one to many to a many to many relationship. With the former A user was assigned a companyId upon registering. The only documents they could return from the database was controlled with a where statement in my Web Api. Now that a User can be assigned many companies I need to change that where statement to do the same thing. So far I have created the junction table. I am having problems accessing it and returning it correctly.
Company Class
public class Company
{
public int CompanyId { get; set; }
public string CompanyName { get; set; }
public int UserCompanyId { get; set; }
public virtual UserCompany UserCompany { get; set; }
}
UserClass
public class ApplicationUser : IdentityUser
{
public async Task<ClaimsIdentity>
GenerateUserIdentityAsync(UserManager<ApplicationUser> manager)
{
var userIdentity = await manager
.CreateIdentityAsync(this, DefaultAuthenticationTypes.ApplicationCookie);
return userIdentity;
}
public int UserCompanyId { get; set; }
public virtual UserCompany UserCompany { get; set; }
}
Junction Table
public class UserCompany
{
[Key]
public int UCompanyId { get; set; }
public string Id { get; set; }
public int CompanyId { get; set; }
}
ApiController
public IEnumerable<Document> GetDocuments()
{
var manager = new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(new ApplicationDbContext()));
var user = manager.FindById(User.Identity.GetUserId());
using (var context = new ApplicationDbContext())
{
return context.UserCompanies
.Where(j => j.CompanyId == user.UserCompany.CompanyId)
.ToList();
}
}
The Error is coming at the .ToList()
Error 1 Cannot implicitly convert type 'System.Collections.Generic.List' to 'System.Collections.Generic.IEnumerable'. An explicit conversion exists (are you missing a cast?)
Update
// GET api/<controller>
public List<Document> GetDocuments()
{
var manager = new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(new ApplicationDbContext()));
var user = manager.FindById(User.Identity.GetUserId());
using (var context = new ApplicationDbContext())
{
return context.Documents
.Where(j => j.CompanyId == user.UserCompany.UCompanyId)
.ToList();
}
}
Document Class
public class Document
{
public int DocumentId { get; set; }
public DateTime DocumentDate { get; set; }
public string DocumentUrl { get; set; }
public DateTime DocumentUploadDate { get; set; }
public string DocumentUploadedBy { get; set; }
public int CompanyId { get; set; }
public virtual Company Company { get; set; }
}
I changed IEnumberable to List. I am still not doing it right,I am getting a error in my ApiController
Non-static method requires a target.
I posted my Document Class as well. I am lost on how to make this work. First time with a many to many relationship
Here is the stacktrace
at System.Reflection.RuntimeMethodInfo.CheckConsistency(Object target)
at System.Reflection.RuntimeMethodInfo.InvokeArgumentsCheck(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at System.Reflection.RuntimeMethodInfo.Invoke(Object obj, BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at System.Reflection.RuntimePropertyInfo.GetValue(Object obj, BindingFlags invokeAttr, Binder binder, Object[] index, CultureInfo culture)
at System.Reflection.RuntimePropertyInfo.GetValue(Object obj, Object[] index)
at System.Data.Entity.Core.Objects.ELinq.QueryParameterExpression.TryGetFieldOrPropertyValue(MemberExpression me, Object instance, Object& memberValue)
at System.Data.Entity.Core.Objects.ELinq.QueryParameterExpression.TryEvaluatePath(Expression expression, ConstantExpression& constantExpression)
at System.Data.Entity.Core.Objects.ELinq.QueryParameterExpression.EvaluateParameter(Object[] arguments)
at System.Data.Entity.Core.Objects.ELinq.ELinqQueryState.GetExecutionPlan(Nullable1 forMergeOption)
at System.Data.Entity.Core.Objects.ObjectQuery1.<>c__DisplayClass7.b__6()
at System.Data.Entity.Core.Objects.ObjectContext.ExecuteInTransaction[T](Func1 func, IDbExecutionStrategy executionStrategy, Boolean startLocalTransaction, Boolean releaseConnectionOnSuccess)
at System.Data.Entity.Core.Objects.ObjectQuery1.<>c__DisplayClass7.b__5()
at System.Data.Entity.SqlServer.DefaultSqlExecutionStrategy.Execute[TResult](Func1 operation)
at System.Data.Entity.Core.Objects.ObjectQuery1.GetResults(Nullable1 forMergeOption)
at System.Data.Entity.Core.Objects.ObjectQuery1..GetEnumerator>b__0()
at System.Data.Entity.Internal.LazyEnumerator1.MoveNext()
at System.Collections.Generic.List1..ctor(IEnumerable1 collection)
at System.Linq.Enumerable.ToList[TSource](IEnumerable1 source)
at TransparentEnergy.ControllersAPI.apiDocumentUserController.GetDocuments() in c:\Development\TransparentEnergy\TransparentEnergy\ControllersAPI\apiDocumentUserController.cs:line 29
at lambda_method(Closure , Object , Object[] )
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.<>c__DisplayClass10.b__9(Object instance, Object[] methodParameters)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ActionExecutor.Execute(Object instance, Object[] arguments)
at System.Web.Http.Controllers.ReflectedHttpActionDescriptor.ExecuteAsync(HttpControllerContext controllerContext, IDictionary`2 arguments, CancellationToken cancellationToken)

Answer 1

I think it's because you're returning a List and the type your function return is IEnumerable, try:
public List<Document> GetDocuments()
{
var manager = new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(new ApplicationDbContext()));
var user = manager.FindById(User.Identity.GetUserId());
using (var context = new ApplicationDbContext())
{
return context.UserCompanies
.Where(j => j.CompanyId == user.UserCompany.CompanyId)
.ToList();
}
}