若實體已經存在資料服務中，WCF Data Services 用戶端程式庫可讓您將代表該實體的物件直接附加至 DataServiceContext，且不需先執行查詢。 如需詳細資訊，請參閱更新資料服務 (WCF Data Services)。
本主題的範例使用 Northwind 範例資料服務，以及自動產生的用戶端資料服務類別。 此服務和用戶端資料類別會在您完成 WCF Data Services 快速入門時建立。
範例
下列範例示範如何建立現有的 Customer 物件，此物件包含要儲存至資料服務的變更。 系統會將物件附加至內容，並呼叫 UpdateObject 方法，將附加物件標記為 Modified，然後再呼叫 SaveChanges 方法。
' Create the DataServiceContext using the service URI.
Dim context = New NorthwindEntities(svcUri)
' Define an existing customer to attach, including the key.
Dim customer As Customer = _
customer.CreateCustomer("ALFKI", "Alfreds Futterkiste")
' Set current property values.
customer.Address = "Obere Str. 57"
customer.City = "Berlin"
customer.PostalCode = "12209"
customer.Country = "Germany"
' Set property values to update.
customer.ContactName = "Peter Franken"
customer.ContactTitle = "Marketing Manager"
customer.Phone = "089-0877310"
customer.Fax = "089-0877451"
Try
' Attach the existing customer to the context and mark it as updated.
context.AttachTo("Customers", customer)
context.UpdateObject(customer)
' Send updates to the data service.
context.SaveChanges()
Catch ex As DataServiceClientException
Throw New ApplicationException( _
"An error occurred when saving changes.", ex)
End Try
// Create the DataServiceContext using the service URI.
NorthwindEntities context = new NorthwindEntities(svcUri);
// Define an existing customer to attach, including the key.
Customer customer =
Customer.CreateCustomer("ALFKI", "Alfreds Futterkiste");
// Set current property values.
customer.Address = "Obere Str. 57";
customer.City = "Berlin";
customer.PostalCode = "12209";
customer.Country = "Germany";
// Set property values to update.
customer.ContactName = "Peter Franken";
customer.ContactTitle = "Marketing Manager";
customer.Phone = "089-0877310";
customer.Fax = "089-0877451";
try
{
// Attach the existing customer to the context and mark it as updated.
context.AttachTo("Customers", customer);
context.UpdateObject(customer);
// Send updates to the data service.
context.SaveChanges();
}
catch (DataServiceClientException ex)
{
throw new ApplicationException(
"An error occurred when saving changes.", ex);
}