DataServiceContext.BeginExecute 메서드

public:
generic <typename T>
 IAsyncResult ^ BeginExecute(System::Data::Services::Client::DataServiceQueryContinuation<T> ^ continuation, AsyncCallback ^ callback, System::Object ^ state);

public IAsyncResult BeginExecute<T> (System.Data.Services.Client.DataServiceQueryContinuation<T> continuation, AsyncCallback callback, object state);

member this.BeginExecute : System.Data.Services.Client.DataServiceQueryContinuation<'T> * AsyncCallback * obj -> IAsyncResult

Public Function BeginExecute(Of T) (continuation As DataServiceQueryContinuation(Of T), callback As AsyncCallback, state As Object) As IAsyncResult

형식 매개 변수

매개 변수

반환

작업 상태를 나타내는 IAsyncResult입니다.

설명

제공된 DataServiceQueryContinuation<T> 개체에는 실행할 때 쿼리 결과에 있는 데이터의 다음 페이지를 반환하는 URI가 포함됩니다.

public:
generic <typename TElement>
 IAsyncResult ^ BeginExecute(Uri ^ requestUri, AsyncCallback ^ callback, System::Object ^ state);

public IAsyncResult BeginExecute<TElement> (Uri requestUri, AsyncCallback callback, object state);

member this.BeginExecute : Uri * AsyncCallback * obj -> IAsyncResult

Public Function BeginExecute(Of TElement) (requestUri As Uri, callback As AsyncCallback, state As Object) As IAsyncResult

형식 매개 변수

매개 변수

반환

비동기 작업의 상태를 추적하는 데 사용되는 개체입니다.

예제

다음 예제에서는 메서드를 호출하여 비동기 쿼리를 BeginExecute 실행하여 쿼리를 시작하는 방법을 보여줍니다. 인라인 대리자는 메서드를 EndExecute 호출하여 쿼리 결과를 표시합니다. 이 예제에서는 WCF Data Services 완료할 때 만들어지는 Northwind 데이터 서비스를 기반으로 서비스 참조 추가 도구에서 생성된 를 사용합니다DataServiceContext.

public static void BeginExecuteCustomersQuery()
{
    // Create the DataServiceContext using the service URI.
    NorthwindEntities context = new NorthwindEntities(svcUri);

    // Define the query to execute asynchronously that returns
    // all customers with their respective orders.
    DataServiceQuery<Customer> query = (DataServiceQuery<Customer>)(from cust in context.Customers.Expand("Orders")
                                       where cust.CustomerID == "ALFKI"
                                       select cust);

    try
    {
        // Begin query execution, supplying a method to handle the response
        // and the original query object to maintain state in the callback.
        query.BeginExecute(OnCustomersQueryComplete, query);
    }
    catch (DataServiceQueryException ex)
    {
        throw new ApplicationException(
            "An error occurred during query execution.", ex);
    }
}

// Handle the query callback.
private static void OnCustomersQueryComplete(IAsyncResult result)
{
    // Get the original query from the result.
    DataServiceQuery<Customer> query =
        result as DataServiceQuery<Customer>;

    foreach (Customer customer in query.EndExecute(result))
    {
        Console.WriteLine("Customer Name: {0}", customer.CompanyName);
        foreach (Order order in customer.Orders)
        {
            Console.WriteLine("Order #: {0} - Freight $: {1}",
                order.OrderID, order.Freight);
        }
    }
}

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

    ' Define the delegate to callback into the process
    Dim callback As AsyncCallback = AddressOf OnCustomersQueryComplete

    ' Define the query to execute asynchronously that returns 
    ' all customers with their respective orders.
    Dim query As DataServiceQuery(Of Customer) = _
    context.Customers.Expand("Orders")

    Try
        ' Begin query execution, supplying a method to handle the response
        ' and the original query object to maintain state in the callback.
        query.BeginExecute(callback, query)
    Catch ex As DataServiceQueryException
        Throw New ApplicationException( _
                "An error occurred during query execution.", ex)
    End Try
End Sub
' Handle the query callback.
Private Shared Sub OnCustomersQueryComplete(ByVal result As IAsyncResult)
    ' Get the original query from the result.
    Dim query As DataServiceQuery(Of Customer) = _
        CType(result.AsyncState, DataServiceQuery(Of Customer))

    ' Complete the query execution.
    For Each customer As Customer In query.EndExecute(result)
        Console.WriteLine("Customer Name: {0}", customer.CompanyName)
        For Each order As Order In customer.Orders
            Console.WriteLine("Order #: {0} - Freight $: {1}", _
                    order.OrderID, order.Freight)
        Next
    Next
End Sub

설명

반환된 IAsyncResult 개체는 비동기 작업이 완료된 시점을 확인하는 데 사용됩니다. 자세한 내용은 비동기 작업합니다.

메서드 BeginExecute 는 와 Execute동일한 의미 체계를 사용하지만 이 메서드는 서비스의 결과를 기다리는 동안 이 호출이 처리를 차단하지 않도록 요청을 비동기적으로 보냅니다. 제공된 콜백은 표준 시작-끝 비동기 패턴에 따라 쿼리 결과가 검색되면 호출됩니다.

추가 정보

• 방법: 비동기 데이터 서비스 쿼리 실행(WCF Data Services)