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How to: Create an Object Using the Static Create Method (Entity Framework)

Entity Framework tools consume a conceptual schema definition language (CSDL) file to generate code that defines the object layer. When the data classes are generated, each class is generated with a static create factory method. This method is used to instantiate an object and set all of the properties of the class that cannot be null. The method includes a parameter for every property that has the Nullable="false" attribute applied in the CSDL file. Use this method when creating objects with many required properties.

The examples in this topic are based on the Adventure Works Sales Model. To run the code in this example, you must have already added the AdventureWorks Sales Model to your project and configured your project to use the Entity Framework. To do this, complete the procedures in How to: Manually Configure an Entity Framework Project and How to: Manually Define an Entity Data Model (Entity Framework).

Example

The following is an example CSDL fragment for the SalesOrderHeader type in the 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>

The following is an example of the static CreateSalesOrderHeader method generated for the SalesOrderHeader class in AdventureWorks:

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;
}

The following is an example of how to use the static CreateSalesOrderHeader method to create and save a SalesOrderHeader object:

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());
    }
}

See Also

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