DataServiceContext.UpdateObject(Object) 方法

定义

命名空间:

System.Data.Services.Client

程序集:

System.Data.Services.Client.dll

将 DataServiceContext 中的指定对象的状态更改为 Modified。

public:
 void UpdateObject(System::Object ^ entity);

public void UpdateObject (object entity);

member this.UpdateObject : obj -> unit

Public Sub UpdateObject (entity As Object)

参数

entity

Object

将指定为 Modified 状态的被跟踪实体。

例外

ArgumentNullException

当 entity 为 null 时。

ArgumentException

当 entity 处于 Detached 状态时。

示例

下面的示例检索和修改现有的对象，然后对 UpdateObject 调用 DataServiceContext 方法以将上下文中的项标记为已更新。 调用 SaveChanges 时，HTTP MERGE 消息将会发送到数据服务。 此示例使用DataServiceContext基于 Northwind 数据服务的“添加服务引用”工具生成的 ，该服务是在完成WCF Data Services 时创建的。

string customerId = "ALFKI";

// Create the DataServiceContext using the service URI.
NorthwindEntities context = new NorthwindEntities(svcUri);

// Get a customer to modify using the supplied ID.
var customerToChange = (from customer in context.Customers
                        where customer.CustomerID == customerId
                        select customer).Single();

// Change some property values.
customerToChange.CompanyName = "Alfreds Futterkiste";
customerToChange.ContactName = "Maria Anders";
customerToChange.ContactTitle = "Sales Representative";

try
{
    // Mark the customer as updated.
    context.UpdateObject(customerToChange);

    // Send the update to the data service.
    context.SaveChanges();
}
catch (DataServiceRequestException  ex)
{
    throw new ApplicationException(
        "An error occurred when saving changes.", ex);
}

Dim customerId = "ALFKI"

' Create the DataServiceContext using the service URI.
Dim context = New NorthwindEntities(svcUri)

' Get a customer to modify using the supplied ID.
Dim customerToChange = (From customer In context.Customers _
                        Where customer.CustomerID = customerId _
                        Select customer).Single()

' Change some property values.
customerToChange.CompanyName = "Alfreds Futterkiste"
customerToChange.ContactName = "Maria Anders"
customerToChange.ContactTitle = "Sales Representative"

Try
    ' Mark the customer as updated.
    context.UpdateObject(customerToChange)

    ' Send the update to the data service.
    context.SaveChanges()
Catch ex As DataServiceRequestException
    Throw New ApplicationException( _
            "An error occurred when saving changes.", ex)
End Try