ObjectContext.Connection 属性

定义

命名空间:

System.Data.Objects

程序集:

System.Data.Entity.dll

获取对象上下文使用的连接。

public:
 property System::Data::Common::DbConnection ^ Connection { System::Data::Common::DbConnection ^ get(); };

public System.Data.Common.DbConnection Connection { get; }

member this.Connection : System.Data.Common.DbConnection

Public ReadOnly Property Connection As DbConnection

属性值

DbConnection

一个作为连接的 DbConnection 对象

例外

ObjectDisposedException

当释放了 ObjectContext 实例时。

示例

本示例创建一个 EntityConnection 对象，该对象将传递到长时间运行的 ObjectContext 的构造函数中。 此连接以手动方式建立。 EntityConnection 对象和 ObjectContext 对象都是手动释放的。

// Define the order ID for the order we want.
int orderId = 43680;

// Create an EntityConnection.
EntityConnection conn =
    new EntityConnection("name=AdventureWorksEntities");

// Create a long-running context with the connection.
AdventureWorksEntities context =
    new AdventureWorksEntities(conn);

try
{
    // Explicitly open the connection.
    if (conn.State != ConnectionState.Open)
    {
        conn.Open();
    }

    // Execute a query to return an order.
    SalesOrderHeader order =
        context.SalesOrderHeaders.Where(
        "it.SalesOrderID = @orderId", new ObjectParameter("orderId", orderId))
        .Execute(MergeOption.AppendOnly).First();

    // Change the status of the order.
    order.Status = 1;

    // You do not have to call the Load method to load the details for the order,
    // because  lazy loading is set to true
    // by the constructor of the AdventureWorksEntities object.
    // With  lazy loading set to true the related objects are loaded when
    // you access the navigation property. In this case SalesOrderDetails.

    // Delete the first item in the order.
    context.DeleteObject(order.SalesOrderDetails.First());

    // Save changes.
    if (0 < context.SaveChanges())
    {
        Console.WriteLine("Changes saved.");
    }

    // 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 = 1,
        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);

    // Save changes again.
    if (0 < context.SaveChanges())
    {
        Console.WriteLine("Changes saved.");
    }
}
catch (InvalidOperationException ex)
{
    Console.WriteLine(ex.ToString());
}
finally
{
    // Explicitly dispose of the context and the connection.
    context.Dispose();
    conn.Dispose();
}

注解

此属性返回传递给构造函数或在构造过程中创建的连接对象。 连接的所有权由所使用的构造函数决定。

另请参阅

• 使用对象（实体框架）