I have the following generic code to update a disconnected entity:
public T UpdateItem(T entity)
{
this._dbSet.Attach(entity);
this._dbContext.Entry(entity).State = System.Data.EntityState.Modified;
this._dbContext.SaveChanges();
return entity;
}
If my entity contains navigation properties, those do not get attached and set to modified. Is there a way I can change this generic method to attach and set to modified, all navigation properties as well?
You can do it with reflection. Here's an extension method to find all the related collections. If all of your Entities implement some standard interface you'll be able to make a similar method to find the non collection navigation properties (that implement your interface).
public static class ContextExtensions
{
public static IEnumerable<IEnumerable<dynamic>> GetCollections(this object o)
{
var result = new List<IEnumerable<dynamic>>();
foreach (var prop in o.GetType().GetProperties())
{
if (typeof(IEnumerable<dynamic>).IsAssignableFrom(prop.PropertyType))
{
var get = prop.GetGetMethod();
if (!get.IsStatic && get.GetParameters().Length == 0)
{
var enumerable = (IEnumerable<dynamic>)get.Invoke(o, null);
if (enumerable != null) result.Add(enumerable);
}
}
}
return result;
}
}
This should add the current objects navigation properties
var collections = entity.GetCollections();
foreach (var collection in collections)
{
foreach (var r in collection)
{
if (_this._dbSet.Entry(r).State == System.Data.EntityState.Detached)
{
this._dbSet.Attach(r);
this._dbContext.Entry(r).State = System.Data.EntityState.Modified;
}
}
}
Related
i'm using SQLite Provider with Entity Frame work in .Net 4.5
conferControlEntities.Configuration.LazyLoadingEnabled = true;
conferControlEntities.Configuration.ProxyCreationEnabled = true;
conferControlEntities.Configuration.AutoDetectChangesEnabled = true;
conferControlEntities.Configuration.ValidateOnSaveEnabled = true;
and i am also using inheritance in the Entity Framework
so i cannot use the include in the query as i can't include the derived objects navigation property
so i have fillNavigationPropty method in Poco classes which will make a call to the Navigation properties and try to fill them
but whenever i check it will be null
using (var context = GetContext(false,true))
{
var queryable = context.Delegates.Where(i => i.ParentId == id);
foreach (var entity in queryable)
{
entity.FillNavigationProperties();
list.Add(WrapperFactory.Create(entity) as TU);
}
return new ObservableCollection<TU>(list);
}
POCO Example
public class TempPOCO
{
public virtual AnotherPCOCCLassTYpe NavigationProperty1{get;set;}
public void FillNavigationProperties()
{
var tempcall = NavigationProperty1;
}
}
I have a repository class with the following code to update entities that have changed.
However I get an error
"The relationship between the two objects cannot be defined because they are attached to different ObjectContext objects."
However I cant see that the context has changed since it is a property of my repository.
Inside the repository I have
protected void InnerUpdate(params T[] items)
{
DbSet<T> dbSet = ((DbContext)this.context).Set<T>();
foreach (T item in items)
{
object id1 = item.GetProperty("Id");
T originalEntity = dbSet.Find(id1);
((DbContext)this.context).Entry(originalEntity).CurrentValues.SetValues(item);
var navProps = GetNavigationProperties(originalEntity);
foreach (var navProp in navProps)
{
//Set originalEntity prop value to modifiedEntity value
navProp.SetValue(originalEntity, navProp.GetValue(item));
}
}
}
this.context.SaveChanges(); // Error occurs here
}
public List<PropertyInfo> GetNavigationProperties(T entity )
{
var t = entity.GetType();
ObjectContext objectContex = ((IObjectContextAdapter)((DbContext)this.context)).ObjectContext;
var elementType = objectContex.CreateObjectSet<T>().EntitySet.ElementType;
var properties = new List<PropertyInfo>();
var entityType = entity.GetType();
foreach (var navigationProperty in elementType.NavigationProperties)
{
properties.Add(entityType.GetProperty(navigationProperty.Name));
}
return properties;
}
I wonder if the problem is due to calling CreateObjectSet ? Is there a different way to do this?
I am using EF6.1
I changed the code as follows and got it working
var navProps = GetNavigationProperties(originalEntity);
foreach (var navProp in navProps)
{
//Set originalEntity prop value to modifiedEntity value
var newval = (LoggedEntity) navProp.GetValue(item);
object entity = null;
if (newval != null)
{
var tp = navProp.PropertyType;
var entities = ((DbContext)this.context).Set(tp);
entity = entities.Find(newval.Id);
}
navProp.SetValue(originalEntity, entity);
}
I am tinkering with WebAPI to create a generic implementation for entity framework. I am able to implement most of the methods just fine, but am finding PUT to be tricky in non-trivial cases. The implementation most commonly found online works for simple entities:
[HttpPut]
[ActionName("Endpoint")]
public virtual T Put(T entity)
{
var db = GetDbContext();
var entry = db.Entry(entity);
entry.State = EntityState.Modified;
var set = db.Set<T>();
set.Attach(entity);
db.SaveChanges();
return entity;
}
...but does not delete or update child lists:
public class Invoice
{
...
public virtual InvoiceLineItem {get; set;} //Attach method doesn't address these
}
In an MVC Controller, you could simply use "UpdateModel" and it would add/update/delete children as needed, however that method is not available on ApiController. I understand that some code would be necessary to get the original item from the database, and that it would need to use Include to get the child lists, but can't quite figure out the best way to replicate UpdateModel's functionality:
[HttpPut]
[ActionName("Endpoint")]
public virtual T Put(T entity)
{
var db = GetDbContext();
var original = GetOriginalFor(entity);
//TODO: Something similar to UpdateModel(original), such as UpdateModel(original, entity);
db.SaveChanges();
return original;
}
How can I implement UpdateModel OR somehow implement Put in such a way that it will handle child lists?
The routine dont validate entity, but fill the pre-existent entity.
protected virtual void UpdateModel<T>(T original, bool overrideForEmptyList = true)
{
var json = ControllerContext.Request.Content.ReadAsStringAsync().Result;
UpdateModel<T>(json, original, overrideForEmptyList);
}
private void UpdateModel<T>(string json, T original, bool overrideForEmptyList = true)
{
var newValues = JsonConvert.DeserializeObject<Pessoa>(json);
foreach (var property in original.GetType().GetProperties())
{
var isEnumerable = property.PropertyType.GetInterfaces().Any(t => t.IsGenericType && t.GetGenericTypeDefinition() == typeof(IEnumerable<>));
if (isEnumerable && property.PropertyType != typeof(string))
{
var propertyOriginalValue = property.GetValue(original, null);
if (propertyOriginalValue != null)
{
var propertyNewValue = property.GetValue(newValues, null);
if (propertyNewValue != null && (overrideForEmptyList || ((IEnumerable<object>)propertyNewValue).Any()))
{
property.SetValue(original, null);
}
}
}
}
JsonConvert.PopulateObject(json, original);
}
public void Post()
{
var sample = Pessoa.FindById(12);
UpdateModel(sample);
}
I have a many-to-many relationship between two entities - Media and MediaCollection. I want to check if a certain Media already exists in a collection. I can do this as follows:
mediaCollection.Media.Any(m => m.id == mediaId)
However, mediaCollection.Media is an ICollection, so to me this looks like it will have to retrieve every Media in the collection from the database just to make this check. As there could be many media in a collection, this seems very inefficient. I'n thinking that I should use a method of IQueryable, but I can't see how to do this for many-to-many relationships.
How can I check for the existence of the relationship without retrieving the whole collection?
EDIT
I am generating the EF data model from my database, then using the built in VS POCO T4 templates to generate my data context and entity classes. I think the problem is that the generated code does not return EntityCollection for the navigation properties, but instead ObjectSet. ObjectSet implements IQueryable, but does not expose a CreateSourceQuery() method.
Here is a stripped down version of the relevant lines from the context:
public partial class Entities : ObjectContext
{
public const string ConnectionString = "name=Entities";
public const string ContainerName = "Entities";
#region Constructors
public Entities()
: base(ConnectionString, ContainerName)
{
this.ContextOptions.LazyLoadingEnabled = true;
}
public Entities(string connectionString)
: base(connectionString, ContainerName)
{
this.ContextOptions.LazyLoadingEnabled = true;
}
public Entities(EntityConnection connection)
: base(connection, ContainerName)
{
this.ContextOptions.LazyLoadingEnabled = true;
}
#endregion
#region ObjectSet Properties
public ObjectSet<MediaCollection> MediaCollections
{
get { return _mediaCollections ?? (_mediaCollections = CreateObjectSet<MediaCollection>("MediaCollections")); }
}
private ObjectSet<MediaCollection> _mediaCollections;
// snipped many more
#endregion
}
And here is a stripped down version of the class for the MediaCollection entity:
public partial class MediaCollection
{
#region Primitive Properties
// snipped
#endregion
#region Navigation Properties
public virtual ICollection<Medium> Media
{
get
{
if (_media == null)
{
var newCollection = new FixupCollection<Medium>();
newCollection.CollectionChanged += FixupMedia;
_media = newCollection;
}
return _media;
}
set
{
if (!ReferenceEquals(_media, value))
{
var previousValue = _media as FixupCollection<Medium>;
if (previousValue != null)
{
previousValue.CollectionChanged -= FixupMedia;
}
_media = value;
var newValue = value as FixupCollection<Medium>;
if (newValue != null)
{
newValue.CollectionChanged += FixupMedia;
}
}
}
}
private ICollection<Medium> _media;
private void FixupMedia(object sender, NotifyCollectionChangedEventArgs e)
{
if (e.NewItems != null)
{
foreach (Medium item in e.NewItems)
{
if (!item.MediaCollections.Contains(this))
{
item.MediaCollections.Add(this);
}
}
}
if (e.OldItems != null)
{
foreach (Medium item in e.OldItems)
{
if (item.MediaCollections.Contains(this))
{
item.MediaCollections.Remove(this);
}
}
}
}
// snip
#endregion
}
And finally, here is the FixupCollection that the template also generates:
public class FixupCollection<T> : ObservableCollection<T>
{
protected override void ClearItems()
{
new List<T>(this).ForEach(t => Remove(t));
}
protected override void InsertItem(int index, T item)
{
if (!this.Contains(item))
{
base.InsertItem(index, item);
}
}
}
You can do that but you need a context for that:
bool exists = context.Entry(mediaCollection)
.Collection(m => m.Media)
.Query()
.Any(x => x.Id == mediaId);
Edit:
If you are using ObjectContext API with proxied POCOs instead of DbContext API the former sample will not work. You can try this:
context.ContextOptions.LazyLoadingEnabled = false;
bool exists = ((EntityCollection<Media>)mediaCollection.Media).CreateSourceQuery()
.Any(x => x.Id == mediaId);
context.ContextOptions.LazyLoadingEnabled = true;
So it seems that the built in VS POCO T4 template does not generate anything equivalent to CreateSourceQuery(). No matter! We can code it ourselves. If you add the following code at to the context's .tt file and regenerate:
public ObjectQuery<T> CreateNavigationSourceQuery<T>(object entity, string navigationProperty)
{
var ose = ObjectStateManager.GetObjectStateEntry(entity);
var rm = ObjectStateManager.GetRelationshipManager(entity);
var entityType = (System.Data.Metadata.Edm.EntityType)ose.EntitySet.ElementType;
var navigation = entityType.NavigationProperties[navigationProperty];
var relatedEnd = rm.GetRelatedEnd(navigation.RelationshipType.FullName, navigation.ToEndMember.Name);
return ((dynamic)relatedEnd).CreateSourceQuery();
}
then we can check for the existence of a many-to-many as follows:
var exists = _context.CreateNavigationSourceQuery<Medium>(mediaCollection, "Media")
.Any(m => m.Id == medium.Id);
Props to Rowan's answer on Using CreateSourceQuery in CTP4 Code First for this one.
Try,
mediaCollection.CreateSourceQuery()
.Any(....
CreateSourceQuery will create IQueryable for the association.
In Asp.net MVC the url structure goes like
http://example.com/{controller}/{action}/{id}
For each "controller", say http://example.com/blog, there is a BlogController.
But my {controller} portion of the url is not decided pre-hand, but it is dynamically determined at run time, how do I create a "dynamic controller" that maps anything to the same controller which then based on the value and determines what to do?
Same thing with {action}, if the {action} portion of my url is also dynamic, is there a way to program this scenario?
Absolutely! You'll need to override the DefaultControllerFactory to find a custom controller if one doesn't exist. Then you'll need to write an IActionInvoker to handle dynamic action names.
Your controller factory will look something like:
public class DynamicControllerFactory : DefaultControllerFactory
{
private readonly IServiceLocator _Locator;
public DynamicControllerFactory(IServiceLocator locator)
{
_Locator = locator;
}
protected override Type GetControllerType(string controllerName)
{
var controllerType = base.GetControllerType(controllerName);
// if a controller wasn't found with a matching name, return our dynamic controller
return controllerType ?? typeof (DynamicController);
}
protected override IController GetControllerInstance(Type controllerType)
{
var controller = base.GetControllerInstance(controllerType) as Controller;
var actionInvoker = _Locator.GetInstance<IActionInvoker>();
if (actionInvoker != null)
{
controller.ActionInvoker = actionInvoker;
}
return controller;
}
}
Then your action invoker would be like:
public class DynamicActionInvoker : ControllerActionInvoker
{
private readonly IServiceLocator _Locator;
public DynamicActionInvoker(IServiceLocator locator)
{
_Locator = locator;
}
protected override ActionDescriptor FindAction(ControllerContext controllerContext,
ControllerDescriptor controllerDescriptor, string actionName)
{
// try to match an existing action name first
var action = base.FindAction(controllerContext, controllerDescriptor, actionName);
if (action != null)
{
return action;
}
// #ray247 The remainder of this you'd probably write on your own...
var actionFinders = _Locator.GetAllInstances<IFindAction>();
if (actionFinders == null)
{
return null;
}
return actionFinders
.Select(f => f.FindAction(controllerContext, controllerDescriptor, actionName))
.Where(d => d != null)
.FirstOrDefault();
}
}
You can see a lot more of this code here. It's an old first draft attempt by myself and a coworker at writing a fully dynamic MVC pipeline. You're free to use it as a reference and copy what you want.
Edit
I figured I should include some background about what that code does. We were trying to dynamically build the MVC layer around a domain model. So if your domain contained a Product class, you could navigate to products\alls to see a list of all products. If you wanted to add a product, you'd navigate to product\add. You could go to product\edit\1 to edit a product. We even tried things like allowing you to edit properties on an entity. So product\editprice\1?value=42 would set the price property of product #1 to 42. (My paths might be a little off, I can't recall the exact syntax anymore.) Hope this helps!
After a little more reflection, there may be a bit simpler way for you to handle the dynamic action names than my other answer. You'll still need to override the default controller factory. I think you could define your route like:
routes.MapRoute("Dynamic", "{controller}/{command}/{id}", new { action = "ProcessCommand" });
Then on your default/dynamic controller you'd have
public ActionResult ProcessCommand(string command, int id)
{
switch(command)
{
// whatever.
}
}
You need to write your own IControllerFactory (or perhaps derive from DefaultControllerFactory) and then register it with ControllerBuilder.
Iam working with it in .Core but i'll share it's MVC version for all, after that i will share the core version
case OwnerType.DynamicPage:
var dp = mediator.Handle(new Domain.DynamicPages.DynamicPageDtoQuery { ShopId = ShopId, SeoId = seoSearchDto.Id }.AsSingle());
if (dp != null)
{
return GetDynamicPage(dp.Id);
}
break;
// some codes
private ActionResult GetDynamicPage(int id)
{
var routeObj = new
{
action = "Detail",
controller = "DynamicPage",
id = id
};
var bController = DependencyResolver.Current.GetService<DynamicPageController>();
SetControllerContext(bController, routeObj);
return bController.Detail(id);
}
// and
private void SetControllerContext(ControllerBase controller, object routeObj)
{
RouteValueDictionary routeValues = new RouteValueDictionary(routeObj);
var vpd = RouteTable.Routes["Default"].GetVirtualPath(this.ControllerContext.RequestContext, routeValues);
RouteData routeData = new RouteData();
foreach (KeyValuePair<string, object> kvp in routeValues)
{
routeData.Values.Add(kvp.Key, kvp.Value);
}
foreach (KeyValuePair<string, object> kvp in vpd.DataTokens)
{
routeData.DataTokens.Add(kvp.Key, kvp.Value);
}
routeData.Route = vpd.Route;
if (routeData.RouteHandler == null)
routeData.RouteHandler = new MvcRouteHandler();
controller.ControllerContext = new ControllerContext(this.ControllerContext.HttpContext, routeData, controller);
}