model-defined functions are discussed here:
https://msdn.microsoft.com/en-us/library/vstudio/dd456857(v=vs.110).aspx
https://msdn.microsoft.com/en-us/library/dd456812.aspx
Entity Framework 6 Code First function mapping
http://www.c-sharpcorner.com/UploadFile/ff2f08/model-defined-function/
are these supported by EF6.1.2?
I'm stepping through the Edm/DbModel stuff and I can't for the life of me work out where the <Function> element in the csdl is supposed to be parsed, because it's not making it into the EdmModel (EdmModel.AddItem(EdmFunction) isn't getting called)
ExpressionConverter.FindFunction looks in EdmModel._functions, and _functions is only added to by EdmModel.AddItem(EdmFunction) and that's only called by the extension method EdmModelExtensions.AddFunction(), and I cannot find anywhere in the EntityFramework source code that calls that function. I must be missing something simple...
more: I gave up on defining the Function in the edmx and now I'm creating my EdmFunction programatically and adding it in a custom IConceptualModelConvention.Apply() method:
class CustomFunctionConvention : IConceptualModelConvention<EdmModel>
{
public void Apply(EdmModel item, DbModel model)
{
var functionPayload = new EdmFunctionPayload () {
CommandText = "CAST (strValue AS int)",
Parameters = new [] {
FunctionParameter.Create("strValue", PrimitiveType.GetEdmPrimitiveType(PrimitiveTypeKind.String).GetEdmPrimitiveType(), ParameterMode.In),
},
ReturnParameters = new [] {
FunctionParameter.Create("ReturnValue", PrimitiveType.GetEdmPrimitiveType(PrimitiveTypeKind.Int32).GetEdmPrimitiveType(), ParameterMode.ReturnValue),
},
IsComposable = true,
};
var function = EdmFunction.Create("ParseInt", "MyNamespace", DataSpace.CSpace, functionPayload, null);
model.ConceptualModel.AddItem(function);
}
}
but now I'm getting a bunch of schema errors in EdmItemCollection.LoadItems() :
Schema specified is not valid. Errors:
(0,0) : error 0005: The 'Aggregate' attribute is not allowed.
(0,0) : error 0005: The 'BuiltIn' attribute is not allowed.
(0,0) : error 0005: The 'NiladicFunction' attribute is not allowed.
(0,0) : error 0005: The 'IsComposable' attribute is not allowed.
(0,0) : error 0005: The 'ParameterTypeSemantics' attribute is not allowed.
(0,0) : error 0005: The 'Schema' attribute is not allowed.
(0,0) : error 0005: The 'Mode' attribute is not allowed.
It seems, model defined functions are usable with code first. Here is a version for your ParseInt example :
namespace EfTestModelFunctions
{
public class CustomFunctionConvention : IConceptualModelConvention<EdmModel>
{
public void Apply(EdmModel item, DbModel model)
{
var functionParseInt = new EdmFunctionPayload()
{
CommandText = String.Format("CAST(strValue AS {0})", PrimitiveType.GetEdmPrimitiveType(PrimitiveTypeKind.Int32)),
Parameters = new[] {
FunctionParameter.Create("strValue", PrimitiveType.GetEdmPrimitiveType(PrimitiveTypeKind.String), ParameterMode.In),
},
ReturnParameters = new[] {
FunctionParameter.Create("ReturnValue", PrimitiveType.GetEdmPrimitiveType(PrimitiveTypeKind.Int32), ParameterMode.ReturnValue),
},
IsComposable = true
};
var function = EdmFunction.Create("ParseInt", model.ConceptualModel.EntityTypes.First().NamespaceName, DataSpace.CSpace, functionParseInt, null);
model.ConceptualModel.AddItem(function);
}
}
public class RootDataContext : DbContext
{
public RootDataContext()
: base("Data Source=******")
{
Database.SetInitializer(new NullDatabaseInitializer<RootDataContext>());
}
protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
modelBuilder.Conventions.Add<CustomFunctionConvention>();
}
public DbSet<RootEntity> Roots { get; set; }
// declare the function with the Context's NameSpace
[DbFunction("EfTestModelFunctions", "ParseInt")]
public static int ParseInt(string value)
{
throw new NotImplementedException();
}
}
}
usage will then be :
var query = ctx.Roots.Where(r => RootDataContext.ParseInt(r.StringProperty)==123);
Also, it seems there is an issue when database migration/initialization is involved. See
UpForGrabs: Unblock creation of model defined functions in model conventions
Related
I've built an extension for Microsoft.EntityFrameworkCore that implements the AddOrUpdateMethod. It's working fine, but with entities with a composite primary key the AnyAsync method return always false, even if there are objects with the same key.
This is the method:
public static async Task AddOrUpdateAsync<TEntity>(this DbSet<TEntity> table, Expression<Func<TEntity, object>> key, Expression<Func<TEntity, bool>> deleteExpression, params TEntity[] entities) where TEntity : class
{
var getKeyFunction = key.Compile();
var getShouldDeleteFunction = deleteExpression.Compile();
var context = GetDbContext(table);
foreach (var entity in entities)
{
var primaryKey = getKeyFunction(entity);
var body = Expression.Equal(Expression.Convert(key.Body, primaryKey.GetType()), Expression.Constant(primaryKey));
Expression<Func<TEntity, bool>> query = Expression.Lambda<Func<TEntity, bool>>(body, key.Parameters);
var exist = await table.AnyAsync(query);
context.Entry(entity).State = exist
? getShouldDeleteFunction(entity) ? EntityState.Deleted : EntityState.Modified
: getShouldDeleteFunction(entity) ? EntityState.Detached : EntityState.Added;
}
}
private static DbContext GetDbContext<T>(this DbSet<T> table) where T : class
{
var infrastructure = table as IInfrastructure<IServiceProvider>;
var serviceProvider = infrastructure.Instance;
var currentDbContext = serviceProvider.GetService(typeof(ICurrentDbContext)) as ICurrentDbContext;
return currentDbContext.Context;
}
and I'm using it like this:
await db.Reports.AddOrUpdateAsync(r => new { r.Number, r.Year }, r => r.Active == false, response.Reports.ToArray());
I think that's happening because I'm using an anonymous type as the key, but I've no idea how to fix this.
The problem seems to be the usage of the anonymous type constant expression, which currently is causing client evaluation, and C# operator == compares anonymous types by reference, hence always returns false.
The trick to get the desired server translation is to "invoke" the key expression with entity by replacing the parameter with Expression.Constant(entity) (Expression.Invoke doesn't work in this case)
So remove the line var getKeyFunction = key.Compile(); as no longer needed, and use the following:
foreach (var entity in entities)
{
var parameter = key.Parameters[0];
var body = Expression.Equal(
key.Body,
key.Body.ReplaceParameter(parameter, Expression.Constant(entity))
);
var query = Expression.Lambda<Func<TEntity, bool>>(body, parameter);
var exist = await table.AnyAsync(query);
// ...
}
where ReplaceParameter is the usual expression helper method:
public static partial class ExpressionUtils
{
public static Expression ReplaceParameter(this Expression expression, ParameterExpression source, Expression target)
=> new ParameterReplacer { Source = source, Target = target }.Visit(expression);
class ParameterReplacer : ExpressionVisitor
{
public ParameterExpression Source;
public Expression Target;
protected override Expression VisitParameter(ParameterExpression node)
=> node == Source ? Target : node;
}
}
I'm attempting to run MediatR with Autofac in .NET Framework 4.6.2.
My registration:
public class MediatorModule : Autofac.Module
{
protected override void Load(ContainerBuilder builder)
{
builder.RegisterSource(new ContravariantRegistrationSource());
builder.RegisterAssemblyTypes(typeof(IMediator ).Assembly).AsImplementedInterfaces();
builder.RegisterType<HealthCheckQueryHandler>().As<IRequestHandler<HealthCheckQuery, HttpStatusCode>>();
}
}
My controller:
[RoutePrefix("api/v1/healthcheck")]
public class HealthCheckController : ApiController
{
private readonly IMediator _mediator;
public HealthCheckController(IMediator mediator)
{
_mediator = mediator;
}
[HttpGet]
[Route("")]
public async Task<HttpStatusCode> Get()
{
var query = new HealthCheckQuery();
var result = await _mediator.Send(query);
return result;
}
}
When I try to hit this api method, I receive the following error:
None of the constructors found with 'Autofac.Core.Activators.Reflection.DefaultConstructorFinder' on type 'MediatR.Mediator' can be invoked with the available services and parameters:\r\nCannot resolve parameter 'MediatR.ServiceFactory serviceFactory' of constructor 'Void .ctor(MediatR.ServiceFactory)
The wiki (https://github.com/jbogard/MediatR/wiki) asks us to register SingleInstanceFactory and MultiInstanceFactory. But Visual Studio is not able to resolve either of these symbols.
How can I resolve this to get MediatR working with Autofac?
I know this is an old post, but in case anyone else googles for this.
You're missing registering the ServiceFactory instance.
builder.Register<ServiceFactory>(ctx =>
{
var c = ctx.Resolve<IComponentContext>();
return t => c.Resolve(t);
});
Taken from here: MediatR Examples
I assume you are using Mediatr v3.0.x.
You are missing the registrations for the SingleInstanceFactory and MultiInstanceFactory as here below.
builder.Register<SingleInstanceFactory>(ctx => {
IComponentContext c = ctx.Resolve<IComponentContext>();
return type => {
Object o;
return c.TryResolve(type, out o) ? o : null;
};
});
builder.Register<MultiInstanceFactory>(ctx => {
IComponentContext c = ctx.Resolve<IComponentContext>();
return type => (IEnumerable<Object>)c.Resolve(typeof(IEnumerable<>).MakeGenericType(type));
});
I'm working with EF 4.5 and DbContext. At business rules layer level, I should implement checks to avoid change entity value properties in some entity scenarios. Sample: StartProjecteDate should be readonly if ProjectIsStarted but not in other status.
I follow DRY principle, for this reason, I should be able to inspect readonly properties list from context and also from UI.
My question:
Is there a DataAnnotation validator that can dynamically set properties as readonly?
(and if not, is there a different / better solution to this problem?)
Notice than I'm working with Web Forms (and Telerik) architecture, a clean and elegant pattern will be welcome.
I'm trying to set and get at run time EditableAttribute as Jesse Webb explains, but I'm not able to get dataannotation attributes from property, my code:
<EditableAttribute(False)>
<MaxLength(400, ErrorMessage:="MÃ xim 400 caracters")>
Public Property NomInvertebrat As String
Edited Nov 8 2013 after digging docs, it seems that dataanottions if for class but for instance object itself. Perhaps an iReadonlyableProperties interface may be a way.
I have a class containing extension methods that lets me read data annotations like this:
int maxRefLen = ReflectionAPI.GetProperty<Organisation, String>(x => x.Name)
.GetAttribute<StringLengthAttribute>()
.GetValueOrDefault(x => x.MaximumLength, 256);
So if you use it you should be able to do get the value of the EditableAttribute like this:
bool isEditable = ReflectionAPI.GetProperty<Foo, String>(x => x.NomInvertebrat)
.GetAttribute<EditableAttribute>()
.GetValueOrDefault(x => x.AllowEdit, true);
As for setting the data annotations at run-time, I haven't done it myself but I have read that there is a solution here: Setting data-annotations at runtime
Getting a list of all data annotations of a particular type I think would entail reading the entity framework metadata. Again I haven't tried this.
If you add that together I personally think it feels clunky rather than elegant, but you have asked for a solution using DataAnnotations and something more elegant would probably mean getting into your architecture.
I would be inclined to do this:
public bool StartDateIsReadOnly
{
//use this property client-side to disable the input
get{ return Project.IsStarted;}
}
//Implement IValidatable object to do server side validation
public IEnumerable<ValidationResult> Validate(ValidationContext validationContext
{
bool startdateIsChanged = // I'll leave you to work out this bit
var results = new List<ValidationResult>();
if(StartDateIsReadOnly && startdateIsChanged)
results.Add(new ValidationResult("Start Date cannot be changed after project is started");
}
Here is the ReflectionAPI class:
Please note that the class includes part of a hack that #JonSkeet posted and described as "evil". I personally think this bit ain't so bad, but you should read the following references:
Override a generic method for value types and reference types.
Evil code - overload resolution workaround
public static class ReflectionAPI
{
public static int GetValueOrDefault<TInput>(this TInput a, Func<TInput, int> func, int defaultValue)
where TInput : Attribute
//Have to restrict to struct or you get the error:
//The type 'R' must be a non-nullable value type in order to use it as parameter 'T' in the generic type or method 'System.Nullable<T>'
{
if (a == null)
return defaultValue;
return func(a);
}
public static Nullable<TResult> GetValueOrDefault<TInput, TResult>(this TInput a, Func<TInput, TResult> func, Nullable<TResult> defaultValue)
where TInput : Attribute
where TResult : struct
//Have to restrict to struct or you get the error:
//The type 'R' must be a non-nullable value type in order to use it as parameter 'T' in the generic type or method 'System.Nullable<T>'
{
if (a == null)
return defaultValue;
return func(a);
}
//In order to constrain to a class without interfering with the overload that has a generic struct constraint
//we need to add a parameter to the signature that is a reference type restricted to a class
public class ClassConstraintHack<T> where T : class { }
//The hack means we have an unused parameter in the signature
//http://msmvps.com/blogs/jon_skeet/archive/2010/11/02/evil-code-overload-resolution-workaround.aspx
public static TResult GetValueOrDefault<TInput, TResult>(this TInput a, Func<TInput, TResult> func, TResult defaultValue, ClassConstraintHack<TResult> ignored = default(ClassConstraintHack<TResult>))
where TInput : Attribute
where TResult : class
{
if (a == null)
return defaultValue;
return func(a);
}
//I don't go so far as to use the inheritance trick decribed in the evil code overload resolution blog,
//just create some overloads that take nullable types - and I will just keep adding overloads for other nullable type
public static bool? GetValueOrDefault<TInput>(this TInput a, Func<TInput, bool?> func, bool? defaultValue)
where TInput : Attribute
{
if (a == null)
return defaultValue;
return func(a);
}
public static int? GetValueOrDefault<TInput>(this TInput a, Func<TInput, int?> func, int? defaultValue)
where TInput : Attribute
{
if (a == null)
return defaultValue;
return func(a);
}
public static T GetAttribute<T>(this PropertyInfo p) where T : Attribute
{
if (p == null)
return null;
return p.GetCustomAttributes(false).OfType<T>().LastOrDefault();
}
public static PropertyInfo GetProperty<T, R>(Expression<Func<T, R>> expression)
{
if (expression == null)
return null;
MemberExpression memberExpression = expression.Body as MemberExpression;
if (memberExpression == null)
return null;
return memberExpression.Member as PropertyInfo;
}
}
.NET allows you to dynamically change structure of Class by implementing System.ComponentModel.ICustomTypeDescriptor. Most serializers support this interface.
// Sample Serialization
foreach(PropertyDescriptor p in TypeDescriptor.GetProperties(obj)){
string name = p.PropertyName;
object value = p.GetValue(obj);
}
Internally TypeDescriptor uses Reflection, but the implementation allows us to override reflection attributes easily.
Here are three steps of implementation,
// Implement System.ComponentModel.ICustomTypeDescriptor Interface on
// your Entity
public class MyEntity: System.ComponentModel.ICustomTypeDescriptor
{
....
// most methods needs only call to default implementation as shown below
System.ComponentModel.AttributeCollection
System.ComponentModel.ICustomTypeDescriptor.GetAttributes()
{
return TypeDescriptor.GetAttributes(this, true);
}
string System.ComponentModel.ICustomTypeDescriptor.GetClassName()
{
return TypeDescriptor.GetClassName(this, true);
}
string System.ComponentModel.ICustomTypeDescriptor.GetComponentName()
{
return TypeDescriptor.GetComponentName(this, true);
}
System.ComponentModel.TypeConverter System.ComponentModel.ICustomTypeDescriptor.GetConverter()
{
return TypeDescriptor.GetConverter(this, true);
}
System.ComponentModel.EventDescriptor System.ComponentModel.ICustomTypeDescriptor.GetDefaultEvent()
{
return TypeDescriptor.GetDefaultEvent(this, true);
}
System.ComponentModel.PropertyDescriptor System.ComponentModel.ICustomTypeDescriptor.GetDefaultProperty()
{
return TypeDescriptor.GetDefaultProperty(this, true);
}
object System.ComponentModel.ICustomTypeDescriptor.GetEditor(Type editorBaseType)
{
return TypeDescriptor.GetEditor(this, editorBaseType, true);
}
System.ComponentModel.EventDescriptorCollection System.ComponentModel.ICustomTypeDescriptor.GetEvents(Attribute[] attributes)
{
return TypeDescriptor.GetEvents(this, attributes, true);
}
System.ComponentModel.EventDescriptorCollection System.ComponentModel.ICustomTypeDescriptor.GetEvents()
{
return TypeDescriptor.GetEvents(this, true);
}
System.ComponentModel.PropertyDescriptorCollection System.ComponentModel.ICustomTypeDescriptor.GetProperties(Attribute[] attributes)
{
return TypeDescriptor.GetProperties(this, attributes, true);
}
object System.ComponentModel.ICustomTypeDescriptor.GetPropertyOwner(System.ComponentModel.PropertyDescriptor pd)
{
return this;
}
// The Only method that needs different implementation is below
System.ComponentModel.PropertyDescriptorCollection
System.ComponentModel.ICustomTypeDescriptor.GetProperties()
{
// ... you are supposed to create new instance of
// PropertyDescriptorCollection with PropertyDescriptor
PropertyDescriptorCollection pdc = new PropertyDescriptorCollection();
foreach(PropertyDescriptor p in TypeDescriptor.GetProperties(this,true)){
// if readonly..
AtomPropertyDescriptor ap = new AtomPropertyDescriptor(p, p.Name);
// or
AtomPropertyDescriptor ap = new AtomPropertyDescriptor(p, p.Name,
true,
new XmlIgnoreAttribute(),
new ScriptIgnoreAttribute(),
new ReadOnlyAttribute());
pdc.Add(ap);
}
return pdc;
}
}
// And here is the AtomPropertyDescriptorClass
public class AtomPropertyDescriptor : PropertyDescriptor
{
PropertyDescriptor desc;
bool? readOnly = null;
public AtomPropertyDescriptor(PropertyDescriptor pd, string name,
bool? readOnly, params Attribute[] attrs) :
base(name, attrs)
{
desc = pd;
this.readOnly = readOnly;
}
public override bool CanResetValue(object component)
{
return desc.CanResetValue(component);
}
public override Type ComponentType
{
get
{
return desc.ComponentType;
}
}
public override object GetValue(object component)
{
return desc.GetValue(component);
}
public override bool IsReadOnly
{
get
{
if (readOnly.HasValue)
return readOnly.Value;
return desc.IsReadOnly;
}
}
public override Type PropertyType
{
get { return desc.PropertyType; }
}
public override void ResetValue(object component)
{
desc.ResetValue(component);
}
public override void SetValue(object component, object value)
{
desc.SetValue(component, value);
}
public override bool ShouldSerializeValue(object component)
{
return desc.ShouldSerializeValue(component);
}
}
I think what you are looking for is a custom Annotation Attribute like this:
<DisableEditAttribute(this.IsProjectStarted)>
Public Property NomInvertebrat As String
public override bool IsValid(bool value)
{
bool result = true;
// Add validation logic here.
if(value)
{
//Compare Current Value Against DB Value.
}
return result;
}
See MSDN: http://msdn.microsoft.com/en-us/library/cc668224(v=vs.98).aspx
Using Autofac, I have multiple IFoo components that take a run-time parameter in the constructor. I'm using some Metadata from the types along with the run-time parameter to construct and manage running instances.
interface IFoo
{
int RunTimeId { get; }
}
[FooMeta("ShaqFoo")]
class Foo1 : IFoo
{
public Foo1 (int runtTimeId)
{
...
}
[FooMeta("KungFoo")]
class Foo2 : IFoo
{
public Foo2 (int runtTimeId)
{
...
}
Module/Registration something like:
builder.Register<Func<int, Foo1>>(c =>
{
var cc = c.Resolve<IComponentContext>();
return id => cc.Resolve<Foo1>(TypedParameter.From<int>(id));
})
.As<Func<int, IFoo>>()
.WithMetadata<IFooMetaData>(m => m.For(sm => sm.FooType, typeof(Foo1)));
builder.Register<Func<int, Foo2>>(c =>
{
var cc = c.Resolve<IComponentContext>();
return id => cc.Resolve<Foo2>(TypedParameter.From<int>(id));
})
.As<Func<int, IFoo>>()
.WithMetadata<IFooMetaData>(m => m.For(sm => sm.FooType, typeof(Foo2)));
And a component that creates new Foos with the run-time parameters and metadata. I need to be create ALL IFoos for a given run-time parameter, and need to check for existing instances (essentially using Metadata + RunTimeId as a key) before creating.
public class FooActivator
{
public FooActivator(IEnumerable<Lazy<Func<int, IFoo>, IFooMetaData>> fooFactories)
{
m_FooFactories = fooFactories;
}
private void HandleNewRunTimeIdEvent(int id)
{
CreateFoosForNewId(id);
}
private void CreateFoosForNewId(int id)
{
foreach (var fooFactory in m_FooFactories)
{
if (!FooWithThisMetadataAndIdExists(fooFactory.Metadata.FooType, id))
{
var newFoo = fooFactory.Value(id);
}
}
}
}
Obviously, I can enumerate all of the IFoos and check metadata using the Lazy Enumeration, but can't pass in the run-time parameter to Lazy.Value. Seems like I need to pass in an Enumerable of Func<>s somehow, but can't figure out how to attach the metadata. Or maybe I need an entirely different approach?
Just getting my head wrapped around autofac, and hoping there's a clean way to accomplish this. I could settle for just using the concrete Foo type (instead of metadata) if there's a simple way to enumerate all of them (without creating them), and use the type + run-time Id as my key instead.
Updated the code with a working solution. Figured out how to register Factories properly with metadata. Seems to work.
Could anyone help me in assessing why the code below doesn't work. I'm using the common extension method for implementing Include when using IObjectset. In our repositories we were seeing this not returning correctly so I've isolated the code in test app as below. I've also included the interface based Context if this may prove relevant and a screenshot of the relevant model section. This occurs for all Includes on IObjectSet properties not just the DPASelections one I've chosen for this example.
If I update the context to return ObjectSet (still using the POCO entities) rather than IObjectSet it all works fine. When using IObjectSet and the extension method and step through the code I see that the extension method is completing correctly with a call to the ObjectQuery we're casting to but the included entities are never returned on the graph. As said, this works perfectly when I don't interface out the Context and return ObjectSet properties hence calling Include directly on ObjectSet.
I'm not getting any errors on executing the query so this isn't the same as several other questions on SO which refer to compiled queries.
Has anyone else experienced problems with this extension method implementation or can anyone spot what I'm doing wrong here?
Any help very much appreciated.
static void Main(string[] args)
{
using (var context = new AssocEntities())
{
context.ContextOptions.LazyLoadingEnabled = false;
Candidate candidate = context.Candidates
.Include("DPASelections.DPAOption")
.SingleOrDefault(c => c.Number == "N100064");
//Count is 0 when using ext. method and IObjectSet through AssocContext but correct when using Include
//on ObjectSet through AssocContext
Console.WriteLine("DPASelection count = {0}",candidate.DPASelections.Count);
//This is always null when using IObjectSet and ext. method but populated
//when using Include on ObjectSet
var option = candidate.DPASelections.First().DPAOption;
Console.WriteLine("First DPAOption = {0} : {1}",option.Id,option.Text);
}
Console.ReadLine();
}
}
public static class Extensions
{
public static IQueryable<TSource> Include<TSource>(this IQueryable<TSource> source, string path)
{
var objectQuery = source as ObjectQuery<TSource>;
if (objectQuery != null)
{
objectQuery.Include(path);
}
return source;
}
}
//Subset of custom context implementing IObjectSet as returns.
//Works fine when I return ObjectSet rather than IObjectSet and use
//the Include method directly
public partial class AssocEntities : ObjectContext
{
public const string ConnectionString = "name=AssocEntities";
public const string ContainerName = "AssocEntities";
#region Constructors
public AssocEntities()
: base(ConnectionString, ContainerName)
{
this.ContextOptions.LazyLoadingEnabled = true;
}
public AssocEntities(string connectionString)
: base(connectionString, ContainerName)
{
this.ContextOptions.LazyLoadingEnabled = true;
}
public AssocEntities(EntityConnection connection)
: base(connection, ContainerName)
{
this.ContextOptions.LazyLoadingEnabled = true;
}
#endregion
#region IObjectSet Properties
public IObjectSet<Address> Addresses
{
get { return _addresses ?? (_addresses = CreateObjectSet<Address>("Addresses")); }
}
private IObjectSet<Address> _addresses;
public IObjectSet<Answer> Answers
{
get { return _answers ?? (_answers = CreateObjectSet<Answer>("Answers")); }
}
private IObjectSet<Answer> _answers;
public IObjectSet<Candidate> Candidates
{
get { return _candidates ?? (_candidates = CreateObjectSet<Candidate>("Candidates")); }
}
}
And the model...
I needed to replace objectQuery.Include(path); with objectQuery = objectQuery.Include(path);
In .Net framework 4.0 there is a build-in Extentionmethod for Include
just add the System.Data.Entity namespace.
It uses reflection - here is how it works:
private static T CommonInclude<T>(T source, string path)
{
MethodInfo method = source.GetType().GetMethod("Include", DbExtensions.StringIncludeTypes);
if (!(method != (MethodInfo) null) || !typeof (T).IsAssignableFrom(method.ReturnType))
return source;
return (T) method.Invoke((object) source, new object[1]
{
(object) path
});
}