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DataServiceContext.UpdateObject(Object) 方法

  • 參考

定義

命名空間:
System.Data.Services.Client
組件:
System.Data.Services.Client.dll

將 DataServiceContext 中指定之物件的狀態變更成 Modified。

public:
 void UpdateObject(System::Object ^ entity);
public void UpdateObject (object entity);
member this.UpdateObject : obj -> unit
Public Sub UpdateObject (entity As Object)

參數

entity
Object

要指派為 Modified 狀態的已追蹤實體。

例外狀況

ArgumentNullException

當 entity 為 null 時。

ArgumentException

當 entity 處於 Detached 狀態時。

範例

下列範例會擷取並修改現有的物件，然後呼叫 UpdateObject 的 DataServiceContext 方法，將內容中的項目標記為已更新。 呼叫 SaveChanges 時，HTTP MERGE 訊息會傳送到資料服務。 此範例會DataServiceContext根據 Northwind 數據服務使用 Add Service Reference 工具所產生的 ，這是在您完成 WCF Data Services 時所建立的 。

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

適用於