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  • Is looping through the entityreference the correct way?

    - by Jova
    I want to get all users that have a specific role to a list of usernames. Is using .Include to include all the users, and going through the UsersReference the best way to loop through all the users that are associated with the role? I noticed I could not do a foreach(User user in role.Users) but UsersReference seem to work, but is that how it's supposed to be done? Going through the reference? using (var context = new MyEntities()) { List<string> users = new List<string>(); Role role = (from r in context.Roles.Include("Users") where r.RoleName == roleName select r).FirstOrDefault(); foreach (User user in role.UsersReference) users.Add(user.UserName); return users.ToArray(); }

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  • Entity Framework: Setting EntityReference EntityKey causes exception on save

    - by NYSystemsAnalyst
    I have a table with a ModifiedUserID field that is a foreign key to a User table. In entity framework, I'm loading the first table, but not the users table. I have the user ID of the current user, and would like to set the ModifiedUserID to that value for all entities that have been modified prior to saving. Before calling SaveChanges(), I use the ObjectStateManager to get all modified entities. Since I do not have the user object, but I do have the user ID, I set the EntityReference.EntityKey property as follows: entity.UserReference.EntityKey = New EntityKey("MyContainer.User", "UserID", DatabaseUserID) This works fine, but when I execute SaveChanges(), I receive the following error: A relationship is being added or deleted from an AssociationSet 'FK_Table1_User'. With cardinality constraints, a corresponding 'Table1' must also be added or deleted. Now, I see that setting the EntityReference.EntityKey creates a new AssociationSet entry, but how to I prevent this error?

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  • Weird - "The EntityReference object could not be serialized" when serializing from an ASP.NET Web Si

    - by Mikey Cee
    I have an Entity Framework data model. Part of the model is a Customer entity. The web service provides a method to get a customer, and to receive an updated version of this customer to be persisted. To test this, I created a new ASP.NET web Application, (Solution Add New Project ASP.NET Web Application), then added a reference to my service reference using the standard Add Service Reference dialog. I then call the service using the following code: var client = new CustomerServiceClient(); var customer = client.GetCustomerByID(18); // get it customer.LimitDown = 100; // change it client.SaveCustomer(customer); // persist it Everything works as expected. Now, I do exactly the same thing, but this time with as ASP.NET Web Site (Solution Add New Web Site ASP.NET Web Site). I add the reference in a similar fashion and copy and paste the code above into the new site. But now I get the following exception thrown on the 4th line: System.InvalidOperationException The EntityReference object could not be serialized. This type of object cannot be serialized when the RelationshipManager belongs to an entity object that does not implement IEntityWithRelationships. Source Error: Line 2474: Line 2475: public SkyWalkerCustomerService.OperationResult SaveCustomer(SkyWalkerCustomerService.Customer customer) { Line 2476: return base.Channel.SaveCustomer(customer); Line 2477: } Line 2478: } Stack Trace: System.Runtime.Remoting.Proxies.RealProxy.HandleReturnMessage(IMessage reqMsg, IMessage retMsg) +9475203 System.Runtime.Remoting.Proxies.RealProxy.PrivateInvoke(MessageData& msgData, Int32 type) +345 SkyWalkerCustomerService.ICustomerService.SaveCustomer(Customer customer) +0 SkyWalkerCustomerService.CustomerServiceClient.SaveCustomer(Customer customer) in c:\Windows\Microsoft.NET\Framework\v4.0.30128\Temporary ASP.NET Files\testsite2\dd2bcf8d\f95604ff\App_WebReferences.fz4h7x7l.0.cs:2476 _Default.Page_Load(Object sender, EventArgs e) in c:\Users\Mike\Documents\Repositories\UWC\SkyWalker\TestSite2\Default.aspx.cs:17 System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14 System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35 System.Web.UI.Control.OnLoad(EventArgs e) +91 System.Web.UI.Control.LoadRecursive() +61 System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1966 Googling for this error returns very little. Why doesn't this work?

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  • Mock a Linq to Sql EntityRef using Moq?

    - by Jeremy Holt
    My datacontext contains a table named Userlog with a one to many relationship with table UserProfile. In class UserLog public UserProfile UserProfile { get {return this._UserProfile.Entity;} } In class UserProfile public EntitySet<UserLog> UserLogs { get{return this._UserLogs;} } { set {this._UserLogs.Assign(value); } How would I go about mocking (using Moq) UserLog.UserProfile without changing the autogenerated code? What I would like to do is something like: var mockUserLog = new Mock<UserLog>(); mockUserLog.Setup(c=>c.UserProfile.FirstName).Returns("Fred"); etc I can do this if I go into the designer.cs and make FirstName and UserProfile virtual, however I would like to do this in the partial class. Any ideas? Thanks Jeremy

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  • Java - SAX parser on a XHTML document

    - by Peter
    Hey, I'm trying to write a SAX parser for an XHTML document that I download from the web. At first I was having a problem with the doctype declaration (I found out from here that it was because W3C have intentionally blocked access to the DTD), but I fixed that with: XMLReader reader = parser.getXMLReader(); reader.setFeature("http://apache.org/xml/features/disallow-doctype-decl",true); However, now I'm experiencing a second problem. The SAX parser throws an exception when it reaches some Javascript embedded in the XHTML document: <script type="text/javascript" language="JavaScript"> function checkForm() { answer = true; if (siw && siw.selectingSomething) answer = false; return answer; }// </script> Specifically the parser throws an error once it reaches the &&'s, as it's expecting an entity reference. The exact exception is: `org.xml.sax.SAXParseException: The entity name must immediately follow the '&' in the entity reference. at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.createSAXParseException(ErrorHandlerWrapper.java:198) at com.sun.org.apache.xerces.internal.util.ErrorHandlerWrapper.fatalError(ErrorHandlerWrapper.java:177) at com.sun.org.apache.xerces.internal.impl.XMLErrorReporter.reportError(XMLErrorReporter.java:391) at com.sun.org.apache.xerces.internal.impl.XMLScanner.reportFatalError(XMLScanner.java:1390) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanEntityReference(XMLDocumentFragmentScannerImpl.java:1814) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl$FragmentContentDriver.next(XMLDocumentFragmentScannerImpl.java:3000) at com.sun.org.apache.xerces.internal.impl.XMLDocumentScannerImpl.next(XMLDocumentScannerImpl.java:624) at com.sun.org.apache.xerces.internal.impl.XMLDocumentFragmentScannerImpl.scanDocument(XMLDocumentFragmentScannerImpl.java:486) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:810) at com.sun.org.apache.xerces.internal.parsers.XML11Configuration.parse(XML11Configuration.java:740) at com.sun.org.apache.xerces.internal.parsers.XMLParser.parse(XMLParser.java:110) at com.sun.org.apache.xerces.internal.parsers.AbstractSAXParser.parse(AbstractSAXParser.java:1208) at com.sun.org.apache.xerces.internal.jaxp.SAXParserImpl$JAXPSAXParser.parse(SAXParserImpl.java:525) at MLIAParser.readPage(MLIAParser.java:55) at MLIAParser.main(MLIAParser.java:75)` I suspect (but I don't know) that if I hadn't disabled the DTD then I wouldn't get this error. So, how can I avoid the DTD error and avoid the entity reference error? Cheers, Pete

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  • Entity Framework v1 &hellip; Brief Synopsis and Tips &ndash; Part 2

    - by Rohit Gupta
    Using Entity Framework with ASMX Web sErvices and WCF Web Service: If you use ASMX WebService to expose Entity objects from Entity Framework... then the ASMX Webservice does not  include object graphs, one work around is to use Facade pattern or to use WCF Service. The other important aspect of using ASMX Web Services along with Entity Framework is that the ASMX Client is not aware of the existence of EF v1 since the client solely deals with C# objects (not EntityObjects or ObjectContext). Since the client is not aware of the ObjectContext hence the client cannot participate in change tracking since the client only receives the Current Values and not the Orginal values when the service sends the the Entity objects to the client. Thus there are 2 drawbacks to using EntityFramework with ASMX Web Service: 1. Object state is not maintained... so to overcome this limitation we need insert/update single entity at a time and retrieve the original values for the entity being updated on the server/service end before calling Save Changes. 2. ASMX does not maintain object graphs... i.e. Customer.Reservations or Customer.Reservations.Trip relationships are not maintained. Thus you need to send these relationships separately from service to client. WCF Web Service overcomes the object graph limitation of ASMX Web Service, but we need to insure that we are populating all the non-null scalar properties of all the objects in the object graph before calling Update. WCF Web service still cannot overcome the second limitation of tracking changes to entities at the client end. Also note that the "Customer" class in the Client is very different from the "Customer" class in the Entity Framework Model Entities. They are incompatible with each other hence we cannot cast one to the other. However the .NET Framework translates the client "Customer" Entity to the EFv1 Model "customer" Entity once the entity is serialzed back on the ASMX server end. If you need change tracking enabled on the client then we need to use WCF Data Services which is available with VS 2010. ====================================================================================================== In WCF when adding an object that has relationships, the framework assumes that every object in the object graph needs to be added to store. for e.g. in a Customer.Reservations.Trip object graph, when a Customer Entity is added to the store, the EFv1 assumes that it needs to a add a Reservations collection and also Trips for each Reservation. Thus if we need to use existing Trips for reservations then we need to insure that we null out the Trip object reference from Reservations and set the TripReference to the EntityKey of the desired Trip instead. ====================================================================================================== Understanding Relationships and Associations in EFv1 The Golden Rule of EF is that it does not load entities/relationships unless you ask it to explicitly do so. However there is 1 exception to this rule. This exception happens when you attach/detach entities from the ObjectContext. If you detach an Entity in a ObjectGraph from the ObjectContext, then the ObjectContext removes the ObjectStateEntry for this Entity and all the relationship Objects associated with this Entity. For e.g. in a Customer.Order.OrderDetails if the Customer Entity is detached from the ObjectContext then you cannot traverse to the Order and OrderDetails Entities (that still exist in the ObjectContext) from the Customer Entity(which does not exist in the Object Context) Conversely, if you JOIN a entity that is not in the ObjectContext with a Entity that is in the ObjContext then the First Entity will automatically be added to the ObjContext since relationships for the 2 Entities need to exist in the ObjContext. ========================================================= You cannot attach an EntityCollection to an entity through its navigation property for e.g. you cannot code myContact.Addresses = myAddressEntityCollection ========================================================== Cascade Deletes in EDM: The Designer does not support specifying cascase deletes for a Entity. To enable cascasde deletes on a Entity in EDM use the Association definition in CSDL for the Entity. for e.g. SalesOrderDetail (SOD) has a Foreign Key relationship with SalesOrderHeader (SalesOrderHeader 1 : SalesOrderDetail *) if you specify a cascade Delete on SalesOrderHeader Entity then calling deleteObject on SalesOrderHeader (SOH) Entity will send delete commands for SOH record and all the SOD records that reference the SOH record. ========================================================== As a good design practise, if you use Cascade Deletes insure that Cascade delete facet is used both in the EDM as well as in the database. Even though it is not absolutely mandatory to have Cascade deletes on both Database and EDM (since you can see that just the Cascade delete spec on the SOH Entity in EDM will insure that SOH record and all related SOD records will be deleted from the database ... even though you dont have cascade delete configured in the database in the SOD table) ============================================================== Maintaining relationships in Code When Setting a Navigation property of a Entity (for e.g. setting the Contact Navigation property of Address Entity) the following rules apply : If both objects are detached, no relationship object will be created. You are simply setting a property the CLR way. If both objects are attached, a relationship object will be created. If only one of the objects is attached, the other will become attached and a relationship object will be created. If that detached object is new, when it is attached to the context its EntityState will be Added. One important rule to remember regarding synchronizing the EntityReference.Value and EntityReference.EntityKey properties is that when attaching an Entity which has a EntityReference (e.g. Address Entity with ContactReference) the Value property will take precedence and if the Value and EntityKey are out of sync, the EntityKey will be updated to match the Value. ====================================================== If you call .Load() method on a detached Entity then the .Load() operation will throw an exception. There is one exception to this rule. If you load entities using MergeOption.NoTracking, you will be able to call .Load() on such entities since these Entities are accessible by the ObjectContext. So the bottomline is that we need Objectontext to be able to call .Load() method to do deffered loading on EntityReference or EntityCollection. Another rule to remember is that you cannot call .Load() on entities that have a EntityState.Added State since the ObjectContext uses the EntityKey of the Primary (Parent) Entity when loading the related (Child) Entity (and not the EntityKey of the child (even if the EntityKey of the child is present before calling .Load()) ====================================================== You can use ObjContext.Add() to add a entity to the ObjContext and set the EntityState of the new Entity to EntityState.Added. here no relationships are added/updated. You can also use EntityCollection.Add() method to add an entity to another entity's related EntityCollection for e.g. contact has a Addresses EntityCollection so to add a new address use contact.Addresses.Add(newAddress) to add a new address to the Addresses EntityCollection. Note that if the entity does not already exist in the ObjectContext then calling contact.Addresses.Add(myAddress) will cause a new Address Entity to be added to the ObjContext with EntityState.Added and it will also add a RelationshipEntry (a relationship object) with EntityState.Added which connects the Contact (contact) with the new address newAddress. Note that if the entity already exists in the Objectcontext (being part theOtherContact.Addresses Collection), then calling contact.Addresses.Add(existingAddress) will add 2 RelationshipEntry objects to the ObjectStateEntry Collection, one with EntityState.Deleted and the other with EntityState.Added. This implies that the existingAddress Entity is removed from the theOtherContact.Addresses Collection and Added to the contact.Addresses Collection..effectively reassigning the address entity from the theOtherContact to "contact". This is called moving an existing entity to a new object graph. ====================================================== You usually use ObjectContext.Attach() and EntityCollection.Attach() methods usually when you need to reconstruct the ObjectGraph after deserializing the objects as received from a ASMX Web Service Client. Attach is usually used to connect existing Entities in the ObjectContext. When EntityCollection.Attach() is called the EntityState of the RelationshipEntry (the relationship object) remains as EntityState.unchanged whereas when EntityCollection.Add() method is called the EntityState of the relationship object changes to EntityState.Added or EntityState.Deleted as the situation demands. ========================================================= LINQ To Entities Tips: Select Many does Inner Join by default.   for e.g. from c in Contact from a in c.Address select c ... this will do a Inner Join between the Contacts and Addresses Table and return only those Contacts that have a Address. ======================================================== Group Joins Do LEFT Join by default. e.g. from a in Address join c in Contact ON a.Contact.ContactID == c.ContactID Into g WHERE a.CountryRegion == "US" select g; This query will do a left join on the Contact table and return contacts that have a address in "US" region The following query : from c in Contact join a in Address.Where(a1 => a1.CountryRegion == "US") on c.ContactID  equals a.Contact.ContactID into addresses select new {c, addresses} will do a left join on the Address table and return All Contacts. In these Contacts only those will have its Address EntityCollection Populated which have a Address in the "US" region, the other contacts will have 0 Addresses in the Address collection (even if addresses for those contacts exist in the database but are in a different region) ======================================================== Linq to Entities does not support DefaultIfEmpty().... instead use .Include("Address") Query Builder method to do a Left JOIN or use Group Joins if you need more control like Filtering on the Address EntityCollection of Contact Entity =================================================================== Use CreateSourceQuery() on the EntityReference or EntityCollection if you need to add filters during deferred loading of Entities (Deferred loading in EFv1 happens when you call Load() method on the EntityReference or EntityCollection. for e.g. var cust=context.Contacts.OfType<Customer>().First(); var sq = cust.Reservations.CreateSourceQuery().Where(r => r.ReservationDate > new DateTime(2008,1,1)); cust.Reservations.Attach(sq); This populates only those reservations that are older than Jan 1 2008. This is the only way (in EFv1) to Attach a Range of Entities to a EntityCollection using the Attach() method ================================================================== If you need to get the Foreign Key value for a entity e.g. to get the ContactID value from a Address Entity use this :                                address.ContactReference.EntityKey.EntityKeyValues.Where(k=> k.Key == "ContactID")

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  • Entity Framework with ASP.NET MVC. Updating entity problem

    - by Kitaly
    Hi people. I'm trying to update an entity and its related entities as well. For instance, I have a class Car with a property Category and I want to change its Category. So, I have the following methods in the Controller: public ActionResult Edit(int id) { var categories = context.Categories.ToList(); ViewData["categories"] = new SelectList(categories, "Id", "Name"); var car = context.Cars.Where(c => c.Id == id).First(); return PartialView("Form", car); } [AcceptVerbs(HttpVerbs.Post)] public ActionResult Edit(Car car) { var category = context.Categories.Where(c => c.Id == car.Category.Id).First(); car.Category = category; context.UpdateCar(car); context.SaveChanges(); return RedirectToAction("Index"); } The UpdateCar method, in ObjectContext class, follows: public void UpdateCar(Car car) { var attachedCar = Cars.Where(c => c.Id == car.Id).First(); ApplyItemUpdates(attachedCar, car); } private void ApplyItemUpdates(EntityObject originalItem, EntityObject updatedItem) { try { ApplyPropertyChanges(originalItem.EntityKey.EntitySetName, updatedItem); ApplyReferencePropertyChanges(updatedItem, originalItem); } catch (InvalidOperationException ex) { Console.WriteLine(ex.ToString()); } } public void ApplyReferencePropertyChanges(IEntityWithRelationships newEntity, IEntityWithRelationships oldEntity) { foreach (var relatedEnd in oldEntity.RelationshipManager.GetAllRelatedEnds()) { var oldRef = relatedEnd as EntityReference; if (oldRef != null) { var newRef = newEntity.RelationshipManager.GetRelatedEnd(oldRef.RelationshipName, oldRef.TargetRoleName) as EntityReference; oldRef.EntityKey = newRef.EntityKey; } } } The problem is that when I set the Category property after the POST in my controller, the entity state changes to Added instead of remaining as Detached. How can I update one-to-one relationship with Entity Framework and ASP.NET MVC without setting all the properties, one by one like this post?

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  • Campaignresponse entity create in plugin

    - by engcmreng
    I wrote plugin that fire on phonecall step is setstatedynamic. I register post image in step my plugin.I get phonecall entity from postimage. And When i set phonecallid to origanitingactivityid on campaign response ( like campaignResponse.OriginatingActivityId = new EntityReference(); campaignResponse.OriginatingActivityId.LogicalName = PhoneCall.EntityLogicalName; campaignResponse.OriginatingActivityId.Id = phoneCall.ActivityId.Value; ) Plugin throws timeout.(I set serviceproxy,Timeout property 30 minutes,its still throw timeout.) When i dont set originatingactivityid,campaingresponse is created. Any suggestion about this problem.

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  • EF2: Is there a way to add an Entity to EntityCollection without having to load related Entity?

    - by mutex
    I can set an EntityReference on an entity without having to load the relevent entity as follows: this.CategoryReference.EntityKey = new EntityKey("MyEntities.CategorySet", "Id", 12); So I can set the Category for the entity I'm dealing with to whatever category has id 12 without having to hit the database. But is there a way to do this or something similar on an EntityCollection? So if I now have multiple categories instead of just one, I want to now do something like the following, though it doesn't work: // stand-in category var categoryStandIn = new Category { EntityKey = new EntityKey("MyEntities.CategorySet", "Id", 12) } this.Categories.Add(categoryStandIn);

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  • How to save derived type (TPT) in Entity Framework?

    - by Peter Stegnar
    I have problems with saving derived type (TPT) with Entity Framework to database. Let's say I have base entity Animal and derived type Dog. I want to save Dog entity. I thought that I could do it like contex.AddToDogs(), but contex contain only base entity - Animal. So I can only save Animal object - contex.AddToAnimals(). I have also tried with contex.AddObject("Animals", dogInstance), but I get the following error: The member with identity 'NavigationProperty' does not exist in the metadata collection. But I have add EntityReference to the "NavigationProperty". So how to save derived type in EF?

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  • TypeConverter prevents ApplyPropertyChanges in EntityFramework

    - by Felix
    I ran into an interesting problem (hopefully, interesting not just for me :) I am running Entity Framework 1 (.NET 3.5) and ASP.NET MVC 2. I have a Customer class that has many-to-one relationship with Country class (in other words, Country is a lookup table for customers - I described more in this post: http://stackoverflow.com/questions/2404801/explicit-casting-doesnt-work-in-default-model-binding ) I got TypeConverter to work; so I am getting a perfect object into controller's Post method. Create works fine; however, in Edit I am getting the following error when I call ApplyPropertyChanges: The existing object in the ObjectContext is in the Added state. Changes can only be applied when the existing object is in an unchanged or modified state. The controller code is fairly trivial: public ActionResult Edit(Customer customerToEdit) { if (ModelState.IsValid) { Customer cust = (Customer)context.GetObjectByKey( new EntityKey("BAEntities.Customers", "CustomerID", customerToEdit.CustomerID)); context.ApplyPropertyChanges(cust.EntityKey.EntitySetName, customerToEdit); context.SaveChanges(); } return View(...); } If I remove country from the form, it works fine; and if I assign dropdown value to EntityReference "manually" - it works as well. TypeConverter code is also fairly simple, but I've never used TypeConverter before, so I may be missing something here: public override object ConvertFrom(ITypeDescriptorContext typeContext, CultureInfo culture, object value) { if (value is string) { int countryID = Int16.Parse((string)value); Country country = (Country)context.GetObjectByKey( new EntityKey("BAEntities.Countries", "CountryID", countryID)); return country; } return base.ConvertFrom(typeContext, culture, value); }

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  • CRM2011 - "The given key was not present in the dictionary"

    - by DJZorrow
    I am what you call a "n00b" in CRM plugin development. I am trying to write a plugin for Microsoft's Dynamics CRM 2011 that will create a new activity entity when you create a new contact. I want this activity entity to be associated with the contact entity. This is my current code: using System; using System.Collections.Generic; using System.Linq; using System.Text; using Microsoft.Xrm.Sdk; namespace ITPH_CRM_Deactivate_Account_SSP_Disable { public class SSPDisable_Plugin: IPlugin { public void Execute(IServiceProvider serviceProvider) { // Obtain the execution context from the service provider. IPluginExecutionContext context = (IPluginExecutionContext) serviceProvider.GetService(typeof(IPluginExecutionContext)); IOrganizationServiceFactory serviceFactory = (IOrganizationServiceFactory)serviceProvider.GetService(typeof(IOrganizationServiceFactory)); IOrganizationService service = serviceFactory.CreateOrganizationService(context.UserId); if (context.InputParameters.Contains("Target") && context.InputParameters["target"] is Entity) { Entity entity = context.InputParameters["Target"] as Entity; if (entity.LogicalName != "account") { return; } Entity followup = new Entity(); followup.LogicalName = "activitypointer"; followup.Attributes = new AttributeCollection(); followup.Attributes.Add("subject", "Created via Plugin."); followup.Attributes.Add("description", "This is generated by the magic of C# ..."); followup.Attributes.Add("scheduledstart", DateTime.Now.AddDays(3)); followup.Attributes.Add("actualend", DateTime.Now.AddDays(5)); if (context.OutputParameters.Contains("id")) { Guid regardingobjectid = new Guid(context.OutputParameters["id"].ToString()); string regardingobjectidType = "account"; followup["regardingobjectid"] = new EntityReference(regardingobjectidType, regardingobjectid); } service.Create(followup); } } } But when i try to run this code: I get an error when i try to create a new contact in the CRM environment. The error is: "The given key was not present in the dictionary" (Link *1). The error pops up right as i try to save the new contact. Link *1: http://puu.sh/4SXrW.png (Translated bold text: "Error on business process") Thanks for any help or suggestions :)

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  • Entity Framework v1 &ndash; tips and Tricks Part 3

    - by Rohit Gupta
    General Tips on Entity Framework v1 & Linq to Entities: ToTraceString() If you need to know the underlying SQL that the EF generates for a Linq To Entities query, then use the ToTraceString() method of the ObjectQuery class. (or use LINQPAD) Note that you need to cast the LINQToEntities query to ObjectQuery before calling TotraceString() as follows: 1: string efSQL = ((ObjectQuery)from c in ctx.Contact 2: where c.Address.Any(a => a.CountryRegion == "US") 3: select c.ContactID).ToTraceString(); ================================================================================ MARS or MultipleActiveResultSet When you create a EDM Model (EDMX file) from the database using Visual Studio, it generates a connection string with the same name as the name of the EntityContainer in CSDL. In the ConnectionString so generated it sets the MultipleActiveResultSet attribute to true by default. So if you are running the following query then it streams multiple readers over the same connection: 1: using (BAEntities context = new BAEntities()) 2: { 3: var cons = 4: from con in context.Contacts 5: where con.FirstName == "Jose" 6: select con; 7: foreach (var c in cons) 8: { 9: if (c.AddDate < new System.DateTime(2007, 1, 1)) 10: { 11: c.Addresses.Load(); 12: } 13: } 14: } ================================================================================= Explicitly opening and closing EntityConnection When you call ToList() or foreach on a LINQToEntities query the EF automatically closes the connection after all the records from the query have been consumed. Thus if you need to run many LINQToEntities queries over the same connection then explicitly open and close the connection as follows: 1: using (BAEntities context = new BAEntities()) 2: { 3: context.Connection.Open(); 4: var cons = from con in context.Contacts where con.FirstName == "Jose" 5: select con; 6: var conList = cons.ToList(); 7: var allCustomers = from con in context.Contacts.OfType<Customer>() 8: select con; 9: var allcustList = allCustomers.ToList(); 10: context.Connection.Close(); 11: } ====================================================================== Dispose ObjectContext only if required After you retrieve entities using the ObjectContext and you are not explicitly disposing the ObjectContext then insure that your code does consume all the records from the LinqToEntities query by calling .ToList() or foreach statement, otherwise the the database connection will remain open and will be closed by the garbage collector when it gets to dispose the ObjectContext. Secondly if you are making updates to the entities retrieved using LinqToEntities then insure that you dont inadverdently dispose of the ObjectContext after the entities are retrieved and before calling .SaveChanges() since you need the SAME ObjectContext to keep track of changes made to the Entities (by using ObjectStateEntry objects). So if you do need to explicitly dispose of the ObjectContext do so only after calling SaveChanges() and only if you dont need to change track the entities retrieved any further. ======================================================================= SQL InjectionAttacks under control with EFv1 LinqToEntities and LinqToSQL queries are parameterized before they are sent to the DB hence they are not vulnerable to SQL Injection attacks. EntitySQL may be slightly vulnerable to attacks since it does not use parameterized queries. However since the EntitySQL demands that the query be valid Entity SQL syntax and valid native SQL syntax at the same time. So the only way one can do a SQLInjection Attack is by knowing the SSDL of the EDM Model and be able to write the correct EntitySQL (note one cannot append regular SQL since then the query wont be a valid EntitySQL syntax) and append it to a parameter. ====================================================================== Improving Performance You can convert the EntitySets and AssociationSets in a EDM Model into precompiled Views using the edmgen utility. for e.g. the Customer Entity can be converted into a precompiled view using edmgen and all LinqToEntities query against the contaxt.Customer EntitySet will use the precompiled View instead of the EntitySet itself (the same being true for relationships (EntityReference & EntityCollections of a Entity)). The advantage being that when using precompiled views the performance will be much better. The syntax for generating precompiled views for a existing EF project is : edmgen /mode:ViewGeneration /inssdl:BAModel.ssdl /incsdl:BAModel.csdl /inmsl:BAModel.msl /p:Chap14.csproj Note that this will only generate precompiled views for EntitySets and Associations and not for existing LinqToEntities queries in the project.(for that use CompiledQuery.Compile<>) Secondly if you have a LinqToEntities query that you need to run multiple times, then one should precompile the query using CompiledQuery.Compile method. The CompiledQuery.Compile<> method accepts a lamda expression as a parameter, which denotes the LinqToEntities query  that you need to precompile. The following is a example of a lamda that we can pass into the CompiledQuery.Compile() method 1: Expression<Func<BAEntities, string, IQueryable<Customer>>> expr = (BAEntities ctx1, string loc) => 2: from c in ctx1.Contacts.OfType<Customer>() 3: where c.Reservations.Any(r => r.Trip.Destination.DestinationName == loc) 4: select c; Then we call the Compile Query as follows: 1: var query = CompiledQuery.Compile<BAEntities, string, IQueryable<Customer>>(expr); 2:  3: using (BAEntities ctx = new BAEntities()) 4: { 5: var loc = "Malta"; 6: IQueryable<Customer> custs = query.Invoke(ctx, loc); 7: var custlist = custs.ToList(); 8: foreach (var item in custlist) 9: { 10: Console.WriteLine(item.FullName); 11: } 12: } Note that if you created a ObjectQuery or a Enitity SQL query instead of the LINQToEntities query, you dont need precompilation for e.g. 1: An Example of EntitySQL query : 2: string esql = "SELECT VALUE c from Contacts AS c where c is of(BAGA.Customer) and c.LastName = 'Gupta'"; 3: ObjectQuery<Customer> custs = CreateQuery<Customer>(esql); 1: An Example of ObjectQuery built using ObjectBuilder methods: 2: from c in Contacts.OfType<Customer>().Where("it.LastName == 'Gupta'") 3: select c This is since the Query plan is cached and thus the performance improves a bit, however since the ObjectQuery or EntitySQL query still needs to materialize the results into Entities hence it will take the same amount of performance hit as with LinqToEntities. However note that not ALL EntitySQL based or QueryBuilder based ObjectQuery plans are cached. So if you are in doubt always create a LinqToEntities compiled query and use that instead ============================================================ GetObjectStateEntry Versus GetObjectByKey We can get to the Entity being referenced by the ObjectStateEntry via its Entity property and there are helper methods in the ObjectStateManager (osm.TryGetObjectStateEntry) to get the ObjectStateEntry for a entity (for which we know the EntityKey). Similarly The ObjectContext has helper methods to get an Entity i.e. TryGetObjectByKey(). TryGetObjectByKey() uses GetObjectStateEntry method under the covers to find the object, however One important difference between these 2 methods is that TryGetObjectByKey queries the database if it is unable to find the object in the context, whereas TryGetObjectStateEntry only looks in the context for existing entries. It will not make a trip to the database ============================================================= POCO objects with EFv1: To create POCO objects that can be used with EFv1. We need to implement 3 key interfaces: IEntityWithKey IEntityWithRelationships IEntityWithChangeTracker Implementing IEntityWithKey is not mandatory, but if you dont then we need to explicitly provide values for the EntityKey for various functions (for e.g. the functions needed to implement IEntityWithChangeTracker and IEntityWithRelationships). Implementation of IEntityWithKey involves exposing a property named EntityKey which returns a EntityKey object. Implementation of IEntityWithChangeTracker involves implementing a method named SetChangeTracker since there can be multiple changetrackers (Object Contexts) existing in memory at the same time. 1: public void SetChangeTracker(IEntityChangeTracker changeTracker) 2: { 3: _changeTracker = changeTracker; 4: } Additionally each property in the POCO object needs to notify the changetracker (objContext) that it is updating itself by calling the EntityMemberChanged and EntityMemberChanging methods on the changeTracker. for e.g.: 1: public EntityKey EntityKey 2: { 3: get { return _entityKey; } 4: set 5: { 6: if (_changeTracker != null) 7: { 8: _changeTracker.EntityMemberChanging("EntityKey"); 9: _entityKey = value; 10: _changeTracker.EntityMemberChanged("EntityKey"); 11: } 12: else 13: _entityKey = value; 14: } 15: } 16: ===================== Custom Property ==================================== 17:  18: [EdmScalarPropertyAttribute(IsNullable = false)] 19: public System.DateTime OrderDate 20: { 21: get { return _orderDate; } 22: set 23: { 24: if (_changeTracker != null) 25: { 26: _changeTracker.EntityMemberChanging("OrderDate"); 27: _orderDate = value; 28: _changeTracker.EntityMemberChanged("OrderDate"); 29: } 30: else 31: _orderDate = value; 32: } 33: } Finally you also need to create the EntityState property as follows: 1: public EntityState EntityState 2: { 3: get { return _changeTracker.EntityState; } 4: } The IEntityWithRelationships involves creating a property that returns RelationshipManager object: 1: public RelationshipManager RelationshipManager 2: { 3: get 4: { 5: if (_relManager == null) 6: _relManager = RelationshipManager.Create(this); 7: return _relManager; 8: } 9: } ============================================================ Tip : ProviderManifestToken – change EDMX File to use SQL 2008 instead of SQL 2005 To use with SQL Server 2008, edit the EDMX file (the raw XML) changing the ProviderManifestToken in the SSDL attributes from "2005" to "2008" ============================================================= With EFv1 we cannot use Structs to replace a anonymous Type while doing projections in a LINQ to Entities query. While the same is supported with LINQToSQL, it is not with LinqToEntities. For e.g. the following is not supported with LinqToEntities since only parameterless constructors and initializers are supported in LINQ to Entities. (the same works with LINQToSQL) 1: public struct CompanyInfo 2: { 3: public int ID { get; set; } 4: public string Name { get; set; } 5: } 6: var companies = (from c in dc.Companies 7: where c.CompanyIcon == null 8: select new CompanyInfo { Name = c.CompanyName, ID = c.CompanyId }).ToList(); ;

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  • Anyone succeeded at injecting Interfaces into Entity Framework 4 Entities, using T4?

    - by Ciel
    Hello: POCO sort of leaves me wanting: (how can I say I use DI/IoC, if the Repository is not the only place that is creating the entities?)...hence my desire to lock it down, get rid of the temptation of newing up POCOs or EntityObjects anywhere in the code, and just allowing entity interfaces above the Repository/Factory layer. For a second there, I nearly thought I had it...was editing EF4's T4 in order to inject in an Interface def. Was going swimmingly, compiled and worked, until I got to the Associations... I wrapped them with a ICollection, and renamed the underlying original collection with a prefix of Wrapped. Unfortunately, when run, throws an error: //The Member 'WrappedSubExamples' in the CLR type 'XAct.App.Data.Model.EF4.Example' is not present in the conceptual model type 'XAct.App.Data.Model.Entity.Example'. var examples = context2.CreateObjectSet(); My T4 segment I used was (this may not work, as it's the longest code snippet I've ever posted here...sorry): #region Generic Property Abstraction <# if (navProperty.ToEndMember.RelationshipMultiplicity == RelationshipMultiplicity.Many) {#> //XAct.App Generic Wrapper: <#=code.SpaceAfter(NewModifier(navProperty))#><#=Accessibility.ForProperty(navProperty)#> ICollection<I<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>> <#=code.Escape(navProperty)#> { get { if (_X<#=code.Escape(navProperty)# == null){ _X<#=code.Escape(navProperty)# = new WrappedCollection,<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#(this.<#=(navProperty.ToEndMember.RelationshipMultiplicity == RelationshipMultiplicity.Many)?"Wrapped":""#<#=code.Escape(navProperty)#); } return _X<#=code.Escape(navProperty)#; } } private ICollection _X<#=code.Escape(navProperty)#; <# } else { # <#=code.SpaceAfter(NewModifier(navProperty))#<#=Accessibility.ForProperty(navProperty)# I<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)# <#=code.Escape(navProperty)# { get { return (I<#=code.Escape(navProperty)#)this.Wrapped<#=code.Escape(navProperty)#; } set { this.Wrapped<#=code.Escape(navProperty)# = value as <#=code.Escape(navProperty)#; } } <# } # #endregion which then wraps the original collection, renamed with the prefix 'Wrapped': /// <summary> /// <#=SummaryComment(navProperty)#> /// </summary><#=LongDescriptionCommentElement(navProperty, region.CurrentIndentLevel) #> [XmlIgnoreAttribute()] [SoapIgnoreAttribute()] [DataMemberAttribute()] [EdmRelationshipNavigationPropertyAttribute("<#=navProperty.RelationshipType.NamespaceName#>", "<#=navProperty.RelationshipType.Name#>", "<#=navProperty.ToEndMember.Name#>")] <# if (navProperty.ToEndMember.RelationshipMultiplicity == RelationshipMultiplicity.Many) { #> <#=code.SpaceAfter(NewModifier(navProperty))#><#=Accessibility.ForProperty(navProperty)#> EntityCollection<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>> Wrapped<#=code.Escape(navProperty)#> { <#=code.SpaceAfter(Accessibility.ForGetter(navProperty))#>get { return ((IEntityWithRelationships)this).RelationshipManager.GetRelatedCollection<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>>("<#=navProperty.RelationshipType.FullName#>", "<#=navProperty.ToEndMember.Name#>"); } <#=code.SpaceAfter(Accessibility.ForSetter(navProperty))#>set { if ((value != null)) { ((IEntityWithRelationships)this).RelationshipManager.InitializeRelatedCollection<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>>("<#=navProperty.RelationshipType.FullName#>", "<#=navProperty.ToEndMember.Name#>", value); } } } <# } else { #> <#=code.SpaceAfter(NewModifier(navProperty))#><#=Accessibility.ForProperty(navProperty)#> <#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#> Wrapped<#=code.Escape(navProperty)#> { <#=code.SpaceAfter(Accessibility.ForGetter(navProperty))#>get { return ((IEntityWithRelationships)this).RelationshipManager.GetRelatedReference<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>>("<#=navProperty.RelationshipType.FullName#>", "<#=navProperty.ToEndMember.Name#>").Value; } <#=code.SpaceAfter(Accessibility.ForSetter(navProperty))#>set { ((IEntityWithRelationships)this).RelationshipManager.GetRelatedReference<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>>("<#=navProperty.RelationshipType.FullName#>", "<#=navProperty.ToEndMember.Name#>").Value = value; } } <# string refPropertyName = navProperty.Name + "Reference"; if (entity.Members.Any(m => m.Name == refPropertyName)) { // 6017 is the same error number that EntityClassGenerator uses. Errors.Add(new System.CodeDom.Compiler.CompilerError(SourceCsdlPath, -1, -1, "6017", String.Format(CultureInfo.CurrentCulture, GetResourceString("Template_ConflictingGeneratedNavPropName"), navProperty.Name, entity.FullName, refPropertyName))); } #> /// <summary> /// <#=SummaryComment(navProperty)#> /// </summary><#=LongDescriptionCommentElement(navProperty, region.CurrentIndentLevel)#> [BrowsableAttribute(false)] [DataMemberAttribute()] <#=Accessibility.ForProperty(navProperty)#> EntityReference<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>> <#=refPropertyName#> { <#=code.SpaceAfter(Accessibility.ForGetter(navProperty))#>get { return ((IEntityWithRelationships)this).RelationshipManager.GetRelatedReference<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>>("<#=navProperty.RelationshipType.FullName#>", "<#=navProperty.ToEndMember.Name#>"); } <#=code.SpaceAfter(Accessibility.ForSetter(navProperty))#>set { if ((value != null)) { ((IEntityWithRelationships)this).RelationshipManager.InitializeRelatedReference<<#=MultiSchemaEscape(navProperty.ToEndMember.GetEntityType(), code)#>>("<#=navProperty.RelationshipType.FullName#>", "<#=navProperty.ToEndMember.Name#>", value); } } } <# } The point is...it bugs out. I've tried various solutions...none worked. Any ideas -- or is this just a wild goose chase, and time to give it up?

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  • Can anyone tell me why my XML writer is not writing attributes?

    - by user1632018
    I am writing a parsing tool to help me clean up a large VC++ project before I make .net bindings for it. I am using an XML writer to read an xml file and write out each element to a new file. If an element with a certain name is found, then it executes some code and writes an output value into the elements value. So far it is almost working, except for one thing: It is not copying the attributes. Can anyone tell me why this is happening? Here is a sample of what it is supposed to copy/modify(Includes the attributes): <?xml version="1.0" encoding="utf-8"?> <Project DefaultTargets="Build" ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"> <ItemGroup Label="ProjectConfigurations"> <ProjectConfiguration Include="Debug|Win32"> <Configuration>Debug</Configuration> <Platform>Win32</Platform> </ProjectConfiguration> <ProjectConfiguration Include="Release|Win32"> <Configuration>Release</Configuration> <Platform>Win32</Platform> </ProjectConfiguration> </ItemGroup> <PropertyGroup Label="Globals"> <ProjectGuid>{57900E99-A405-49F4-83B2-0254117D041B}</ProjectGuid> <Keyword>Win32Proj</Keyword> <RootNamespace>libproj</RootNamespace> </PropertyGroup> Here is the output I am getting(No Attributes): <?xml version="1.0" encoding="utf-8"?> <Project> <ItemGroup> <ProjectConfiguration> <Configuration>Debug</Configuration> <Platform>Win32</Platform> </ProjectConfiguration> <ProjectConfiguration> <Configuration>Release</Configuration> <Platform>Win32</Platform> </ProjectConfiguration> </ItemGroup> <PropertyGroup> <ProjectGuid>{57900E99-A405-49F4-83B2-0254117D041B}</ProjectGuid> <Keyword>Win32Proj</Keyword> <RootNamespace>libproj</RootNamespace> Here is my code currently. I have tried every way I can come up with to write the attributes. string baseDir = (textBox2.Text + "\\" + safeFileName); string vcName = Path.GetFileName(textBox1.Text); string vcProj = Path.Combine(baseDir, vcName); using (XmlReader reader = XmlReader.Create(textBox1.Text)) { XmlWriterSettings settings = new XmlWriterSettings(); settings.OmitXmlDeclaration = true; settings.ConformanceLevel = ConformanceLevel.Fragment; settings.Indent = true; settings.CloseOutput = false; using (XmlWriter writer = XmlWriter.Create(vcProj, settings)) { while (reader.Read()) { switch (reader.NodeType) { case XmlNodeType.Element: if (reader.Name == "ClInclude") { string include = reader.GetAttribute("Include"); string dirPath = Path.GetDirectoryName(textBox1.Text); Directory.SetCurrentDirectory(dirPath); string fullPath = Path.GetFullPath(include); //string dirPath = Path.GetDirectoryName(fullPath); copyFile(fullPath, 3); string filename = Path.GetFileName(fullPath); writer.WriteStartElement(reader.Name); writer.WriteAttributeString("Include", "include/" + filename); writer.WriteEndElement(); } else if (reader.Name == "ClCompile" && reader.HasAttributes) { string include = reader.GetAttribute("Include"); string dirPath = Path.GetDirectoryName(textBox1.Text); Directory.SetCurrentDirectory(dirPath); string fullPath = Path.GetFullPath(include); copyFile(fullPath, 2); string filename = Path.GetFileName(fullPath); writer.WriteStartElement(reader.Name); writer.WriteAttributeString("Include", "src/" + filename); writer.WriteEndElement(); } else { writer.WriteStartElement(reader.Name); } break; case XmlNodeType.Text: writer.WriteString(reader.Value); break; case XmlNodeType.XmlDeclaration: case XmlNodeType.ProcessingInstruction: writer.WriteProcessingInstruction(reader.Name, reader.Value); break; case XmlNodeType.Comment: writer.WriteComment(reader.Value); break; case XmlNodeType.Attribute: writer.WriteAttributes(reader, true); break; case XmlNodeType.EntityReference: writer.WriteEntityRef(reader.Value); break; case XmlNodeType.EndElement: writer.WriteFullEndElement(); break; } } } }

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