Child hinzufügen, um die bestehenden übergeordneten Datensatz in entity framework
Meine Beziehung zwischen Mutter und Kind ist, dass Sie sind verbunden durch eine Kante. Es ist ähnlich wie ein gerichteter graph Struktur.
DAL:
public void SaveResource(Resource resource)
{
context.AddToResources(resource); //Should also add children.
context.SaveChanges();
}
public Resource GetResource(int resourceId)
{
var resource = (from r in context.Resources
.Include("ToEdges").Include("FromEdges")
where r.ResourceId == resourceId
select r).SingleOrDefault();
return resource;
}Service:
public void AddChildResource(int parentResourceId, Resource childResource)
{
Resource parentResource = repository.GetResource(parentResourceId);
ResourceEdge inEdge = new ResourceEdge();
inEdge.ToResource = childResource;
parentResource.ToEdges.Add(inEdge);
repository.SaveResource(parentResource);
}Fehler: Ein Objekt mit demselben Schlüssel ist bereits vorhanden in der ObjectStateManager. Das bestehende Objekt wird in den Unveränderten Zustand. Ein Objekt kann nur Hinzugefügt werden, um den ObjectStateManager wieder, wenn es in dem zusätzlichen Zustand.
Bild:
Mir wurde gesagt, dies ist die Reihenfolge, in der Einreichung eines Kindes zu einem bereits vorhandenen parent:
Bekommen Eltern -> Befestigen Kind zu Eltern -> reichen Eltern.
Ist die Reihenfolge, die ich verwendet habe. Der obige code wird extrahiert aus einer ASP.NET MVC 2 Anwendung mit dem repository-pattern.
EDMX-Datei:
<?xml version="1.0" encoding="utf-8"?>
<edmx:Edmx Version="2.0" xmlns:edmx="http://schemas.microsoft.com/ado/2008/10/edmx">
<!-- EF Runtime content -->
<edmx:Runtime>
<!-- SSDL content -->
<edmx:StorageModels>
<Schema Namespace="XDbModel.Store" Alias="Self" Provider="System.Data.SqlClient" ProviderManifestToken="2008" xmlns:store="http://schemas.microsoft.com/ado/2007/12/edm/EntityStoreSchemaGenerator" xmlns="http://schemas.microsoft.com/ado/2009/02/edm/ssdl">
<EntityContainer Name="XDbModelStoreContainer">
<EntitySet Name="Bundles" EntityType="XDbModel.Store.Bundles" store:Type="Tables" Schema="dbo" />
<EntitySet Name="CellProviders" EntityType="XDbModel.Store.CellProviders" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Comments" EntityType="XDbModel.Store.Comments" store:Type="Tables" Schema="dbo" />
<EntitySet Name="LocationPoints" EntityType="XDbModel.Store.LocationPoints" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Locations" EntityType="XDbModel.Store.Locations" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Offers" EntityType="XDbModel.Store.Offers" store:Type="Tables" Schema="dbo" />
<EntitySet Name="PostBundleJunction" EntityType="XDbModel.Store.PostBundleJunction" store:Type="Tables" Schema="dbo" />
<EntitySet Name="PostMedia" EntityType="XDbModel.Store.PostMedia" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Posts" EntityType="XDbModel.Store.Posts" store:Type="Tables" Schema="dbo" />
<EntitySet Name="ResourceEdges" EntityType="XDbModel.Store.ResourceEdges" store:Type="Tables" Schema="dbo" />
<EntitySet Name="ResourceNames" EntityType="XDbModel.Store.ResourceNames" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Resources" EntityType="XDbModel.Store.Resources" store:Type="Tables" Schema="dbo" />
<EntitySet Name="sysdiagrams" EntityType="XDbModel.Store.sysdiagrams" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Users" EntityType="XDbModel.Store.Users" store:Type="Tables" Schema="dbo" />
<EntitySet Name="Votes" EntityType="XDbModel.Store.Votes" store:Type="Tables" Schema="dbo" />
<AssociationSet Name="FK_Comments_Offers" Association="XDbModel.Store.FK_Comments_Offers">
<End Role="Offers" EntitySet="Offers" />
<End Role="Comments" EntitySet="Comments" />
</AssociationSet>
<AssociationSet Name="FK_Comments_Users" Association="XDbModel.Store.FK_Comments_Users">
<End Role="Users" EntitySet="Users" />
<End Role="Comments" EntitySet="Comments" />
</AssociationSet>
<AssociationSet Name="FK_LocationPoints_Locations" Association="XDbModel.Store.FK_LocationPoints_Locations">
<End Role="Locations" EntitySet="Locations" />
<End Role="LocationPoints" EntitySet="LocationPoints" />
</AssociationSet>
<AssociationSet Name="FK_PostBundleJunction_Bundles" Association="XDbModel.Store.FK_PostBundleJunction_Bundles">
<End Role="Bundles" EntitySet="Bundles" />
<End Role="PostBundleJunction" EntitySet="PostBundleJunction" />
</AssociationSet>
<AssociationSet Name="FK_PostBundleJunction_Posts" Association="XDbModel.Store.FK_PostBundleJunction_Posts">
<End Role="Posts" EntitySet="Posts" />
<End Role="PostBundleJunction" EntitySet="PostBundleJunction" />
</AssociationSet>
<AssociationSet Name="FK_Posts_Locations" Association="XDbModel.Store.FK_Posts_Locations">
<End Role="Locations" EntitySet="Locations" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
<AssociationSet Name="FK_Posts_ResourceNames" Association="XDbModel.Store.FK_Posts_ResourceNames">
<End Role="ResourceNames" EntitySet="ResourceNames" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
<AssociationSet Name="FK_Posts_Users" Association="XDbModel.Store.FK_Posts_Users">
<End Role="Users" EntitySet="Users" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
<AssociationSet Name="FK_ResourceEdges_Resources" Association="XDbModel.Store.FK_ResourceEdges_Resources">
<End Role="Resources" EntitySet="Resources" />
<End Role="ResourceEdges" EntitySet="ResourceEdges" />
</AssociationSet>
<AssociationSet Name="FK_ResourceEdges_Resources1" Association="XDbModel.Store.FK_ResourceEdges_Resources1">
<End Role="Resources" EntitySet="Resources" />
<End Role="ResourceEdges" EntitySet="ResourceEdges" />
</AssociationSet>
<AssociationSet Name="FK_ResourceNames_Resources" Association="XDbModel.Store.FK_ResourceNames_Resources">
<End Role="Resources" EntitySet="Resources" />
<End Role="ResourceNames" EntitySet="ResourceNames" />
</AssociationSet>
<AssociationSet Name="FK_Users_Locations" Association="XDbModel.Store.FK_Users_Locations">
<End Role="Locations" EntitySet="Locations" />
<End Role="Users" EntitySet="Users" />
</AssociationSet>
<AssociationSet Name="FK_Votes_Posts" Association="XDbModel.Store.FK_Votes_Posts">
<End Role="Posts" EntitySet="Posts" />
<End Role="Votes" EntitySet="Votes" />
</AssociationSet>
</EntityContainer>
<EntityType Name="Bundles">
<Key>
<PropertyRef Name="BundleId" />
</Key>
<Property Name="BundleId" Type="int" Nullable="false" />
</EntityType>
<EntityType Name="CellProviders">
<Key>
<PropertyRef Name="CellProviderID" />
</Key>
<Property Name="CellProviderID" Type="uniqueidentifier" Nullable="false" />
</EntityType>
<EntityType Name="Comments">
<Key>
<PropertyRef Name="CommentID" />
</Key>
<Property Name="CommentID" Type="uniqueidentifier" Nullable="false" />
<Property Name="ParentPostID" Type="uniqueidentifier" />
<Property Name="OfferPostID" Type="uniqueidentifier" />
<Property Name="UserID" Type="uniqueidentifier" Nullable="false" />
</EntityType>
<EntityType Name="LocationPoints">
<Key>
<PropertyRef Name="LocationPointId" />
</Key>
<Property Name="LocationPointId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="Latitude" Type="float" Nullable="false" />
<Property Name="Longitude" Type="float" Nullable="false" />
<Property Name="Altitude" Type="float" Nullable="false" />
<Property Name="Count" Type="int" Nullable="false" />
<Property Name="LocationId" Type="int" Nullable="false" />
</EntityType>
<EntityType Name="Locations">
<Key>
<PropertyRef Name="LocationId" />
</Key>
<Property Name="LocationId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="Address1" Type="nvarchar" Nullable="false" MaxLength="200" />
<Property Name="Address2" Type="nvarchar" MaxLength="200" />
<Property Name="Address3" Type="nvarchar" MaxLength="200" />
<Property Name="State" Type="nvarchar" Nullable="false" MaxLength="200" />
<Property Name="Country" Type="nvarchar" Nullable="false" MaxLength="200" />
</EntityType>
<EntityType Name="Offers">
<Key>
<PropertyRef Name="OfferID" />
</Key>
<Property Name="OfferID" Type="uniqueidentifier" Nullable="false" />
<Property Name="NeedOffer" Type="uniqueidentifier" Nullable="false" />
<Property Name="ProvisionOffer" Type="uniqueidentifier" Nullable="false" />
</EntityType>
<EntityType Name="PostBundleJunction">
<Key>
<PropertyRef Name="BundleId" />
<PropertyRef Name="PostId" />
</Key>
<Property Name="BundleId" Type="int" Nullable="false" />
<Property Name="PostId" Type="int" Nullable="false" />
</EntityType>
<EntityType Name="PostMedia">
<Key>
<PropertyRef Name="MediaId" />
</Key>
<Property Name="MediaId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="MediaExt" Type="nvarchar" Nullable="false" MaxLength="5" />
<Property Name="PostId" Type="int" Nullable="false" />
<Property Name="SynthId" Type="uniqueidentifier" />
</EntityType>
<EntityType Name="Posts">
<Key>
<PropertyRef Name="PostId" />
</Key>
<Property Name="PostId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="PosterID" Type="uniqueidentifier" Nullable="false" />
<Property Name="BundleId" Type="int" Nullable="false" />
<Property Name="LocationId" Type="int" Nullable="false" />
<Property Name="Tags" Type="uniqueidentifier" />
<Property Name="Quanitity" Type="int" Nullable="false" />
<Property Name="Description" Type="text" Nullable="false" />
<Property Name="ResourceNameId" Type="int" Nullable="false" />
<Property Name="Date" Type="datetime" Nullable="false" />
</EntityType>
<EntityType Name="ResourceEdges">
<Key>
<PropertyRef Name="EdgeId" />
</Key>
<Property Name="Rank" Type="int" Nullable="false" />
<Property Name="EdgeId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="ToResourceId" Type="int" Nullable="false" />
<Property Name="FromResourrceId" Type="int" Nullable="false" />
</EntityType>
<EntityType Name="ResourceNames">
<Key>
<PropertyRef Name="ResourceNameId" />
</Key>
<Property Name="ResourceNameId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="Name" Type="nvarchar" Nullable="false" MaxLength="100" />
<Property Name="ResourceId" Type="int" Nullable="false" />
</EntityType>
<EntityType Name="Resources">
<Key>
<PropertyRef Name="ResourceId" />
</Key>
<Property Name="ResourceId" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="Description" Type="nvarchar" MaxLength="50" />
</EntityType>
<EntityType Name="sysdiagrams">
<Key>
<PropertyRef Name="diagram_id" />
</Key>
<Property Name="name" Type="nvarchar" Nullable="false" MaxLength="128" />
<Property Name="principal_id" Type="int" Nullable="false" />
<Property Name="diagram_id" Type="int" Nullable="false" StoreGeneratedPattern="Identity" />
<Property Name="version" Type="int" />
<Property Name="definition" Type="varbinary(max)" />
</EntityType>
<EntityType Name="Users">
<Key>
<PropertyRef Name="UserID" />
</Key>
<Property Name="UserID" Type="uniqueidentifier" Nullable="false" />
<Property Name="LocationId" Type="int" />
</EntityType>
<EntityType Name="Votes">
<Key>
<PropertyRef Name="VoteId" />
</Key>
<Property Name="VoteId" Type="int" Nullable="false" />
<Property Name="VoterId" Type="uniqueidentifier" Nullable="false" />
<Property Name="VoteContent" Type="int" Nullable="false" />
<Property Name="PostId" Type="int" Nullable="false" />
</EntityType>
<Association Name="FK_Comments_Offers">
<End Role="Offers" Type="XDbModel.Store.Offers" Multiplicity="0..1" />
<End Role="Comments" Type="XDbModel.Store.Comments" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Offers">
<PropertyRef Name="OfferID" />
</Principal>
<Dependent Role="Comments">
<PropertyRef Name="OfferPostID" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_Comments_Users">
<End Role="Users" Type="XDbModel.Store.Users" Multiplicity="1">
<OnDelete Action="Cascade" />
</End>
<End Role="Comments" Type="XDbModel.Store.Comments" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Users">
<PropertyRef Name="UserID" />
</Principal>
<Dependent Role="Comments">
<PropertyRef Name="UserID" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_LocationPoints_Locations">
<End Role="Locations" Type="XDbModel.Store.Locations" Multiplicity="1">
<OnDelete Action="Cascade" />
</End>
<End Role="LocationPoints" Type="XDbModel.Store.LocationPoints" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Locations">
<PropertyRef Name="LocationId" />
</Principal>
<Dependent Role="LocationPoints">
<PropertyRef Name="LocationId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_PostBundleJunction_Bundles">
<End Role="Bundles" Type="XDbModel.Store.Bundles" Multiplicity="1" />
<End Role="PostBundleJunction" Type="XDbModel.Store.PostBundleJunction" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Bundles">
<PropertyRef Name="BundleId" />
</Principal>
<Dependent Role="PostBundleJunction">
<PropertyRef Name="BundleId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_PostBundleJunction_Posts">
<End Role="Posts" Type="XDbModel.Store.Posts" Multiplicity="1" />
<End Role="PostBundleJunction" Type="XDbModel.Store.PostBundleJunction" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Posts">
<PropertyRef Name="PostId" />
</Principal>
<Dependent Role="PostBundleJunction">
<PropertyRef Name="PostId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_Posts_Locations">
<End Role="Locations" Type="XDbModel.Store.Locations" Multiplicity="1" />
<End Role="Posts" Type="XDbModel.Store.Posts" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Locations">
<PropertyRef Name="LocationId" />
</Principal>
<Dependent Role="Posts">
<PropertyRef Name="LocationId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_Posts_ResourceNames">
<End Role="ResourceNames" Type="XDbModel.Store.ResourceNames" Multiplicity="1" />
<End Role="Posts" Type="XDbModel.Store.Posts" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="ResourceNames">
<PropertyRef Name="ResourceNameId" />
</Principal>
<Dependent Role="Posts">
<PropertyRef Name="ResourceNameId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_Posts_Users">
<End Role="Users" Type="XDbModel.Store.Users" Multiplicity="1" />
<End Role="Posts" Type="XDbModel.Store.Posts" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Users">
<PropertyRef Name="UserID" />
</Principal>
<Dependent Role="Posts">
<PropertyRef Name="PosterID" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_ResourceEdges_Resources">
<End Role="Resources" Type="XDbModel.Store.Resources" Multiplicity="1" />
<End Role="ResourceEdges" Type="XDbModel.Store.ResourceEdges" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Resources">
<PropertyRef Name="ResourceId" />
</Principal>
<Dependent Role="ResourceEdges">
<PropertyRef Name="ToResourceId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_ResourceEdges_Resources1">
<End Role="Resources" Type="XDbModel.Store.Resources" Multiplicity="1" />
<End Role="ResourceEdges" Type="XDbModel.Store.ResourceEdges" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Resources">
<PropertyRef Name="ResourceId" />
</Principal>
<Dependent Role="ResourceEdges">
<PropertyRef Name="FromResourrceId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_ResourceNames_Resources">
<End Role="Resources" Type="XDbModel.Store.Resources" Multiplicity="1">
<OnDelete Action="Cascade" />
</End>
<End Role="ResourceNames" Type="XDbModel.Store.ResourceNames" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Resources">
<PropertyRef Name="ResourceId" />
</Principal>
<Dependent Role="ResourceNames">
<PropertyRef Name="ResourceId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_Users_Locations">
<End Role="Locations" Type="XDbModel.Store.Locations" Multiplicity="0..1">
<OnDelete Action="Cascade" />
</End>
<End Role="Users" Type="XDbModel.Store.Users" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Locations">
<PropertyRef Name="LocationId" />
</Principal>
<Dependent Role="Users">
<PropertyRef Name="LocationId" />
</Dependent>
</ReferentialConstraint>
</Association>
<Association Name="FK_Votes_Posts">
<End Role="Posts" Type="XDbModel.Store.Posts" Multiplicity="1">
<OnDelete Action="Cascade" />
</End>
<End Role="Votes" Type="XDbModel.Store.Votes" Multiplicity="*" />
<ReferentialConstraint>
<Principal Role="Posts">
<PropertyRef Name="PostId" />
</Principal>
<Dependent Role="Votes">
<PropertyRef Name="PostId" />
</Dependent>
</ReferentialConstraint>
</Association>
</Schema>
</edmx:StorageModels>
<!-- CSDL content -->
<edmx:ConceptualModels>
<Schema Namespace="XDbModel" Alias="Self" xmlns:annotation="http://schemas.microsoft.com/ado/2009/02/edm/annotation" xmlns="http://schemas.microsoft.com/ado/2008/09/edm">
<EntityContainer Name="XDbEntities" annotation:LazyLoadingEnabled="true">
<EntitySet Name="Bundles" EntityType="XDbModel.Bundle" />
<EntitySet Name="CellProviders" EntityType="XDbModel.CellProvider" />
<EntitySet Name="Comments" EntityType="XDbModel.Comment" />
<EntitySet Name="LocationPoints" EntityType="XDbModel.LocationPoint" />
<EntitySet Name="Locations" EntityType="XDbModel.Location" />
<EntitySet Name="Offers" EntityType="XDbModel.Offer" />
<EntitySet Name="PostMedias" EntityType="XDbModel.PostMedia" />
<EntitySet Name="Posts" EntityType="XDbModel.Post" />
<EntitySet Name="ResourceEdges" EntityType="XDbModel.ResourceEdge" />
<EntitySet Name="ResourceNames" EntityType="XDbModel.ResourceName" />
<EntitySet Name="Resources" EntityType="XDbModel.Resource" />
<EntitySet Name="sysdiagrams" EntityType="XDbModel.sysdiagram" />
<EntitySet Name="Users" EntityType="XDbModel.User" />
<EntitySet Name="Votes" EntityType="XDbModel.Vote" />
<AssociationSet Name="FK_Comments_Offers" Association="XDbModel.FK_Comments_Offers">
<End Role="Offers" EntitySet="Offers" />
<End Role="Comments" EntitySet="Comments" />
</AssociationSet>
<AssociationSet Name="FK_Comments_Users" Association="XDbModel.FK_Comments_Users">
<End Role="Users" EntitySet="Users" />
<End Role="Comments" EntitySet="Comments" />
</AssociationSet>
<AssociationSet Name="FK_LocationPoints_Locations" Association="XDbModel.FK_LocationPoints_Locations">
<End Role="Locations" EntitySet="Locations" />
<End Role="LocationPoints" EntitySet="LocationPoints" />
</AssociationSet>
<AssociationSet Name="FK_Posts_Locations" Association="XDbModel.FK_Posts_Locations">
<End Role="Locations" EntitySet="Locations" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
<AssociationSet Name="FK_Users_Locations" Association="XDbModel.FK_Users_Locations">
<End Role="Locations" EntitySet="Locations" />
<End Role="Users" EntitySet="Users" />
</AssociationSet>
<AssociationSet Name="FK_Posts_ResourceNames" Association="XDbModel.FK_Posts_ResourceNames">
<End Role="ResourceNames" EntitySet="ResourceNames" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
<AssociationSet Name="FK_Posts_Users" Association="XDbModel.FK_Posts_Users">
<End Role="Users" EntitySet="Users" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
<AssociationSet Name="FK_Votes_Posts" Association="XDbModel.FK_Votes_Posts">
<End Role="Posts" EntitySet="Posts" />
<End Role="Votes" EntitySet="Votes" />
</AssociationSet>
<AssociationSet Name="FK_ResourceEdges_Resources" Association="XDbModel.FK_ResourceEdges_Resources">
<End Role="Resources" EntitySet="Resources" />
<End Role="ResourceEdges" EntitySet="ResourceEdges" />
</AssociationSet>
<AssociationSet Name="FK_ResourceEdges_Resources1" Association="XDbModel.FK_ResourceEdges_Resources1">
<End Role="Resources" EntitySet="Resources" />
<End Role="ResourceEdges" EntitySet="ResourceEdges" />
</AssociationSet>
<AssociationSet Name="FK_ResourceNames_Resources" Association="XDbModel.FK_ResourceNames_Resources">
<End Role="Resources" EntitySet="Resources" />
<End Role="ResourceNames" EntitySet="ResourceNames" />
</AssociationSet>
<AssociationSet Name="PostBundleJunction" Association="XDbModel.PostBundleJunction">
<End Role="Bundles" EntitySet="Bundles" />
<End Role="Posts" EntitySet="Posts" />
</AssociationSet>
</EntityContainer>
<EntityType Name="Bundle">
<Key>
<PropertyRef Name="BundleId" />
</Key>
<Property Name="BundleId" Type="Int32" Nullable="false" />
<NavigationProperty Name="Posts" Relationship="XDbModel.PostBundleJunction" FromRole="Bundles" ToRole="Posts" />
</EntityType>
<EntityType Name="CellProvider">
<Key>
<PropertyRef Name="CellProviderID" />
</Key>
<Property Name="CellProviderID" Type="Guid" Nullable="false" />
</EntityType>
<EntityType Name="Comment">
<Key>
<PropertyRef Name="CommentID" />- Welche version von entity-framework / VS2010(?) sind Sie auf?
- VS2010 RC1, nicht, dass der framework-version.
- SingleOrDefault Methode ist Linq2Sql... Verwenden FirstOrDefault in EF statt. Nur eine Beobachtung.
- tatsächlich diese beiden Methoden sind in BEIDEN L2S und EF.. Der Unterschied besteht in Ihrem Verhalten. Wenn Ihre Abfrage mehr als ein Objekt in der Ergebnismenge, dann FirstOrDefault wird wieder die erste. SingleOrDefault wird, statt eine exception zu werfen!
- Guter Punkt. Ich weiß, dass sich beide in EF so gut... Aber Sie haben darauf hingewiesen, die offensichtliche Unterschied.
- Nur um klar zu sein: SingleOrDefault wird nicht unterstützt, EF-3.5. Es wird jetzt unterstützt das EF-4.
Schreibe einen Kommentar
Du musst angemeldet sein, um einen Kommentar abzugeben.
Ah, es ist eigentlich sehr einfach, wenn man darüber nachdenkt..
Das, was du versuchst, es zu tun, fügen Sie die Ressource an den Daten-Kontext, auch wenn diese Ressource-Objekt wurde aus der Datenbank in den ersten Platz. Also der Fehler ist nicht zu Klagen über Ihre Kind-Objekte, sondern über Ihre parent-Objekt! 🙂
Grundsätzlich, wenn Sie kommentieren Sie die erste Zeile in der SaveResource () - Methode sollte es einfach funktionieren!
E. g.:
Oder bewegen Sie einfach die AddChildResource Methode, um Ihre DAL:
Vermutlich ist es beschwerte sich über die childResource nicht in dem Zustand Hinzugefügt. Sie fügte hinzu, es zu dem edge-Objekt, das in der zusätzlichen Status.
Können Sie versuchen, durch die Art und Weise, die Sie festlegen, dass der Verein Runde:-