DataServiceContext.UpdateObject 方法

  • 项目

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

命名空间：  System.Data.Services.Client
程序集：  Microsoft.Data.Services.Client（在 Microsoft.Data.Services.Client.dll 中）

语法

声明
Public Sub UpdateObject ( _
    entity As Object _
)
用法
Dim instance As DataServiceContext
Dim entity As Object

instance.UpdateObject(entity)

public void UpdateObject(
    Object entity
)

public:
void UpdateObject(
    Object^ entity
)

member UpdateObject : 
        entity:Object -> unit 

public function UpdateObject(
    entity : Object
)

参数

异常

异常 条件
ArgumentNullException

当 entity 为 nullnull 引用（在 Visual Basic 中为 Nothing） 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 DataServiceContext 调用 UpdateObject 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。 此示例使用基于 Northwind 数据服务（在您完成 WCF 数据服务?快速入门时创建）的“添加服务引用”工具所生成的 DataServiceContext。

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

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);
}

请参阅

参考

DataServiceContext 类

System.Data.Services.Client 命名空间