Procédure : créer un objet à l'aide d'une méthode create statique (Entity Framework)
Les outils Entity Framework utilisent un fichier CSDL (Conceptual Schema Definition Language) pour générer du code qui définit la couche objet. Lorsque les classes de données sont générées, chaque classe est générée à l'aide d'une méthode de fabrique create statique. Cette méthode permet d'instancier un objet et de définir toutes les propriétés de la classe qui ne peuvent pas être Null. Elle inclut un paramètre pour chaque propriété dont le paramètre Nullable="false" est appliqué dans le fichier CSDL. Utilisez cette méthode lors de la création d'objets ayant de nombreuses propriétés requises.
Les exemples de cette rubrique sont basés sur le modèle de vente Adventure Works Sales Model. Pour exécuter le code de cet exemple, vous devez déjà avoir ajouté le modèle de vente AdventureWorks Sales Model à votre projet et configuré ce dernier pour qu'il utilise Entity Framework. Pour ce faire, exécutez les procédures décrites dans Procédure : configurer manuellement un projet Entity Framework et Procédure : définir manuellement un modèle EDM (Entity Data Model) (Entity Framework).
Exemple
Voici un exemple de fragment CSDL pour le type SalesOrderHeader dans le Modèle de vente AdventureWorks Sales Model (EDM) :
<EntityType Name="SalesOrderHeader">
<Key>
<PropertyRef Name="SalesOrderID" />
</Key>
<Property Name="SalesOrderID" Type="Int32" Nullable="false" />
<Property Name="RevisionNumber" Type="Byte" Nullable="false" />
<Property Name="OrderDate" Type="DateTime" Nullable="false" />
<Property Name="DueDate" Type="DateTime" Nullable="false" />
<Property Name="ShipDate" Type="DateTime" />
<Property Name="Status" Type="Byte" Nullable="false" ConcurrencyMode="Fixed" />
<Property Name="OnlineOrderFlag" Type="Boolean" Nullable="false" />
<Property Name="SalesOrderNumber" Type="String" Nullable="false" MaxLength="25" Unicode="true" FixedLength="false" />
<Property Name="PurchaseOrderNumber" Type="String" MaxLength="25" Unicode="true" FixedLength="false" />
<Property Name="AccountNumber" Type="String" MaxLength="15" Unicode="true" FixedLength="false" />
<Property Name="CustomerID" Type="Int32" Nullable="false" />
<Property Name="SalesPersonID" Type="Int32" />
<Property Name="TerritoryID" Type="Int32" />
<Property Name="ShipMethodID" Type="Int32" Nullable="false" />
<Property Name="CreditCardID" Type="Int32" />
<Property Name="CreditCardApprovalCode" Type="String" MaxLength="15" Unicode="false" FixedLength="false" />
<Property Name="CurrencyRateID" Type="Int32" />
<Property Name="SubTotal" Type="Decimal" Nullable="false" Precision="19" Scale="4" />
<Property Name="TaxAmt" Type="Decimal" Nullable="false" Precision="19" Scale="4" />
<Property Name="Freight" Type="Decimal" Nullable="false" Precision="19" Scale="4" />
<Property Name="TotalDue" Type="Decimal" Nullable="false" Precision="19" Scale="4" />
<Property Name="Comment" Type="String" MaxLength="128" Unicode="true" FixedLength="false" />
<Property Name="rowguid" Type="Guid" Nullable="false" />
<Property Name="ModifiedDate" Type="DateTime" Nullable="false" />
<NavigationProperty Name="Address" Relationship="AdventureWorksModel.FK_SalesOrderHeader_Address_BillToAddressID" FromRole="SalesOrderHeader" ToRole="Address" />
<NavigationProperty Name="Address1" Relationship="AdventureWorksModel.FK_SalesOrderHeader_Address_ShipToAddressID" FromRole="SalesOrderHeader" ToRole="Address" />
<NavigationProperty Name="Contact" Relationship="AdventureWorksModel.FK_SalesOrderHeader_Contact_ContactID" FromRole="SalesOrderHeader" ToRole="Contact" />
<NavigationProperty Name="SalesOrderDetail" Relationship="AdventureWorksModel.FK_SalesOrderDetail_SalesOrderHeader_SalesOrderID" FromRole="SalesOrderHeader" ToRole="SalesOrderDetail" />
</EntityType>
Voici un exemple de la méthode CreateSalesOrderHeader statique générée pour la classe SalesOrderHeader dans AdventureWorks :
Public Shared Function CreateSalesOrderHeader(ByVal salesOrderID As Integer, _
ByVal revisionNumber As Byte, ByVal orderDate As Date, ByVal dueDate As Date, _
ByVal status As Byte, ByVal onlineOrderFlag As Boolean, _
ByVal salesOrderNumber As String, ByVal customerID As Integer, _
ByVal shipMethodID As Integer, ByVal subTotal As Decimal, ByVal taxAmt As Decimal, _
ByVal freight As Decimal, ByVal totalDue As Decimal, ByVal rowguid As Global.System.Guid, _
ByVal modifiedDate As Date) As SalesOrderHeader
Dim salesOrderHeader As SalesOrderHeader = New SalesOrderHeader
salesOrderHeader.SalesOrderID = salesOrderID
salesOrderHeader.RevisionNumber = revisionNumber
salesOrderHeader.OrderDate = orderDate
salesOrderHeader.DueDate = dueDate
salesOrderHeader.Status = status
salesOrderHeader.OnlineOrderFlag = onlineOrderFlag
salesOrderHeader.SalesOrderNumber = salesOrderNumber
salesOrderHeader.CustomerID = customerID
salesOrderHeader.ShipMethodID = shipMethodID
salesOrderHeader.SubTotal = subTotal
salesOrderHeader.TaxAmt = taxAmt
salesOrderHeader.Freight = freight
salesOrderHeader.TotalDue = totalDue
salesOrderHeader.rowguid = rowguid
salesOrderHeader.ModifiedDate = modifiedDate
Return salesOrderHeader
End Function
public static SalesOrderHeader CreateSalesOrderHeader(int salesOrderID,
byte revisionNumber, global::System.DateTime orderDate,
global::System.DateTime dueDate, byte status, bool onlineOrderFlag,
string salesOrderNumber, int customerID, int shipMethodID, decimal subTotal,
decimal taxAmt, decimal freight, decimal totalDue, global::System.Guid rowguid,
global::System.DateTime modifiedDate)
{
SalesOrderHeader salesOrderHeader = new SalesOrderHeader();
salesOrderHeader.SalesOrderID = salesOrderID;
salesOrderHeader.RevisionNumber = revisionNumber;
salesOrderHeader.OrderDate = orderDate;
salesOrderHeader.DueDate = dueDate;
salesOrderHeader.Status = status;
salesOrderHeader.OnlineOrderFlag = onlineOrderFlag;
salesOrderHeader.SalesOrderNumber = salesOrderNumber;
salesOrderHeader.CustomerID = customerID;
salesOrderHeader.ShipMethodID = shipMethodID;
salesOrderHeader.SubTotal = subTotal;
salesOrderHeader.TaxAmt = taxAmt;
salesOrderHeader.Freight = freight;
salesOrderHeader.TotalDue = totalDue;
salesOrderHeader.rowguid = rowguid;
salesOrderHeader.ModifiedDate = modifiedDate;
return salesOrderHeader;
}
Voici un exemple d'utilisation de la méthode CreateSalesOrderHeader statique pour créer et enregistrer un objet SalesOrderHeader :
Dim productId As Integer = 777 'Mountain-100 Black, 44
Dim quantity As Short = 1
Dim lastName As String = "Adams"
Dim firstName As String = "Frances"
Dim invoiceNumber As String = "PO123456"
Dim shipMethod As Integer = 5
Dim specialOffer As Integer = 1
Using advWorksContext As New AdventureWorksEntities()
Try
' Get the Contact for the specific customer
' and the related address.
Dim customer As Contact = advWorksContext.Contact _
.Include("SalesOrderHeader.Address") _
.Where("it.LastName = @lastname", _
New ObjectParameter("lastname", lastName)) _
.Where("it.FirstName = @firstname", _
New ObjectParameter("firstname", firstName)) _
.First()
' Get the customer's address to use to create
' a new order with the same address.
Dim address As Address = customer.SalesOrderHeader _
.First().Address()
' Get the Product with the requested ID.
Dim product As Product = _
advWorksContext.Product.Where("it.ProductID = @product_id", _
New ObjectParameter("product_id", productId)).First()
' Create a new SalesOrderHeader using the static
' CreateSalesOrderHeader method.
Dim order As SalesOrderHeader = _
SalesOrderHeader.CreateSalesOrderHeader( _
1, Convert.ToByte(1), DateTime.Now, DateTime.Today.AddMonths(2), _
Convert.ToByte(1), False, String.Empty, customer.ContactID, shipMethod, _
0, 0, 0, 0, Guid.NewGuid(), DateTime.Now)
' Set addition order properties.
order.Address = address
order.Address1 = address
order.PurchaseOrderNumber = invoiceNumber
' Create a new SalesOrderDetail using the static
' CreateSalesOrderDetail method.
Dim item As SalesOrderDetail = _
SalesOrderDetail.CreateSalesOrderDetail( _
1, 0, quantity, product.ProductID, specialOffer, product.StandardCost, _
0, 0, Guid.NewGuid(), DateTime.Now)
' Add item to the items collection and
' add order to the orders collection.
order.SalesOrderDetail.Add(item)
customer.SalesOrderHeader.Add(order)
' Call a custom method to recalculate totals.
' For more information, see "Customizing Objects."
order.UpdateOrderTotal()
' Save changes pessimistically. This means that changes
' must be accepted manually once the transaction succeeds.
advWorksContext.SaveChanges()
Console.WriteLine("Order created with order number: " _
+ order.SalesOrderNumber)
Catch ex As Exception
Console.WriteLine(ex.ToString())
End Try
End Using
int productId = 777; //Mountain-100 Black, 44
short quantity = 1;
string lastName = @"Adams";
string firstName = @"Frances";
string invoiceNumber = "PO123456";
int shipMethod = 5;
int specialOffer = 1;
using (AdventureWorksEntities advWorksContext =
new AdventureWorksEntities())
{
try
{
// Get the Contact for the specific customer
// and the related address.
Contact customer = advWorksContext.Contact
.Include("SalesOrderHeader.Address")
.Where("it.LastName = @lastname",
new ObjectParameter("lastname", lastName))
.Where("it.FirstName = @firstname",
new ObjectParameter("firstname", firstName))
.First();
// Get the customer's address to use to create
// a new order with the same address.
Address address = customer.SalesOrderHeader
.First().Address;
// Get the Product with the requested ID.
Product product =
advWorksContext.Product.Where("it.ProductID = @product_id",
new ObjectParameter("product_id", productId)).First();
// Create a new SalesOrderHeader using the static
// CreateSalesOrderHeader method.
SalesOrderHeader order = SalesOrderHeader.CreateSalesOrderHeader(0,
Convert.ToByte(1), DateTime.Now, DateTime.Today.AddMonths(2),
Convert.ToByte(1), false, string.Empty, customer.ContactID, shipMethod,
0, 0, 0, 0, Guid.NewGuid(), DateTime.Now);
// Set addition order properties.
order.Address = address;
order.Address1 = address;
order.PurchaseOrderNumber = invoiceNumber;
// Create a new SalesOrderDetail using the static
// CreateSalesOrderDetail method.
SalesOrderDetail item = SalesOrderDetail.CreateSalesOrderDetail(
1, 0, quantity, product.ProductID, specialOffer, product.StandardCost,
0, 0,Guid.NewGuid(), DateTime.Now);
// Add item to the items collection and
// add order to the orders collection.
order.SalesOrderDetail.Add(item);
customer.SalesOrderHeader.Add(order);
// Call a custom method to recalculate totals.
// For more information, see "Customizing Objects."
order.UpdateOrderTotal();
// Save changes pessimistically. This means that changes
// must be accepted manually once the transaction succeeds.
advWorksContext.SaveChanges();
Console.WriteLine("Order created with order number: "
+ order.SalesOrderNumber);
}
catch (Exception ex)
{
Console.WriteLine(ex.ToString());
}
}
Voir aussi
Concepts
Ajout, modification et suppression d'objets (Entity Framework)
Vue d'ensemble d'Object Services (Entity Framework)