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EntityKey Constructor (String, String, Object)

Initializes a new instance of the EntityKey class with an entity set name and specific entity key pair.

Namespace:  System.Data
Assembly:  System.Data.Entity (in System.Data.Entity.dll)

public EntityKey(
	string qualifiedEntitySetName,
	string keyName,
	Object keyValue
)

Parameters

qualifiedEntitySetName
Type: System.String

A String that is the entity set name qualified by the entity container name.

keyName
Type: System.String

A String that is the name of the key.

keyValue
Type: System.Object

An Object that is the key value.

This example is based on the Adventure Works Sales Model. The example shows you how to create and use an EntityKey.

using (AdventureWorksEntities context =
    new AdventureWorksEntities())
{
    try
    {
        // Create the key that represents the order.
        EntityKey orderKey =
            new EntityKey("AdventureWorksEntities.SalesOrderHeaders",
                "SalesOrderID", orderId);

        // Create the stand-in SalesOrderHeader object 
        // based on the specified SalesOrderID.
        SalesOrderHeader order = new SalesOrderHeader();
        order.EntityKey = orderKey;

        // Assign the ID to the SalesOrderID property to matche the key.
        order.SalesOrderID = (int)orderKey.EntityKeyValues[0].Value;

        // Attach the stand-in SalesOrderHeader object.
        context.SalesOrderHeaders.Attach(order);

        // Create a new SalesOrderDetail object. 
        // You can use the static CreateObjectName method (the Entity Framework 
        // adds this method to the generated entity types) instead of the new operator: 
        // SalesOrderDetail.CreateSalesOrderDetail(1, 0, 2, 750, 1, (decimal)2171.2942, 0, 0, 
        //                                         Guid.NewGuid(), DateTime.Today));
        SalesOrderDetail detail = new SalesOrderDetail
        {
            SalesOrderID = orderId,
            SalesOrderDetailID = 0,
            OrderQty = 2,
            ProductID = 750,
            SpecialOfferID = 1,
            UnitPrice = (decimal)2171.2942,
            UnitPriceDiscount = 0,
            LineTotal = 0,
            rowguid = Guid.NewGuid(),
            ModifiedDate = DateTime.Now
        };

        order.SalesOrderDetails.Add(detail);

        context.SaveChanges();
    }
    catch (InvalidOperationException)
    {
        Console.WriteLine("Ensure that the key value matches the value of the object's ID property.");
    }
    catch (UpdateException)
    {
        Console.WriteLine("An error has occured. Ensure that an object with the '{0}' key value exists.",
        orderId);
    }
}

.NET Framework

Supported in: 4.5, 4, 3.5 SP1

.NET Framework Client Profile

Supported in: 4

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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