DataServiceContext.Execute 方法

public:
generic <typename T>
 System::Data::Services::Client::QueryOperationResponse<T> ^ Execute(System::Data::Services::Client::DataServiceQueryContinuation<T> ^ continuation);

public System.Data.Services.Client.QueryOperationResponse<T> Execute<T>(System.Data.Services.Client.DataServiceQueryContinuation<T> continuation);

member this.Execute : System.Data.Services.Client.DataServiceQueryContinuation<'T> -> System.Data.Services.Client.QueryOperationResponse<'T>

Public Function Execute(Of T) (continuation As DataServiceQueryContinuation(Of T)) As QueryOperationResponse(Of T)

類型參數

參數

傳回

回應包含查詢結果下一頁資料的回應。

例外狀況

備註

所提供的 DataServiceQueryContinuation<T> 物件包含 URI，執行時會回傳查詢結果中的下一頁資料。

public:
generic <typename TElement>
 System::Collections::Generic::IEnumerable<TElement> ^ Execute(Uri ^ requestUri);

public System.Collections.Generic.IEnumerable<TElement> Execute<TElement>(Uri requestUri);

member this.Execute : Uri -> seq<'Element>

Public Function Execute(Of TElement) (requestUri As Uri) As IEnumerable(Of TElement)

類型參數

參數

傳回

查詢操作的結果。

例外狀況

範例

此範例使用 do…while 迴圈從資料服務分頁結果載入 Customers 實體。 Execute此方法是透過使用下一個連結 URI 來接收下一頁資料。

// Create the DataServiceContext using the service URI.
NorthwindEntities context = new NorthwindEntities(svcUri);
DataServiceQueryContinuation<Customer> token = null;
int pageCount = 0;

try
{
    // Execute the query for all customers and get the response object.
    QueryOperationResponse<Customer> response =
        context.Customers.Execute() as QueryOperationResponse<Customer>;

    // With a paged response from the service, use a do...while loop
    // to enumerate the results before getting the next link.
    do
    {
        // Write the page number.
        Console.WriteLine("Page {0}:", pageCount++);

        // If nextLink is not null, then there is a new page to load.
        if (token != null)
        {
            // Load the new page from the next link URI.
            response = context.Execute<Customer>(token)
                as QueryOperationResponse<Customer>;
        }

        // Enumerate the customers in the response.
        foreach (Customer customer in response)
        {
            Console.WriteLine("\tCustomer Name: {0}", customer.CompanyName);
        }
    }

    // Get the next link, and continue while there is a next link.
    while ((token = response.GetContinuation()) != null);
}
catch (DataServiceQueryException ex)
{
    throw new ApplicationException(
        "An error occurred during query execution.", ex);
}

' Create the DataServiceContext using the service URI.
Dim context = New NorthwindEntities(svcUri)
Dim token As DataServiceQueryContinuation(Of Customer) = Nothing
Dim pageCount = 0

Try
    ' Execute the query for all customers and get the response object.
    Dim response As QueryOperationResponse(Of Customer) =
        CType(context.Customers.Execute(), QueryOperationResponse(Of Customer))

    ' With a paged response from the service, use a do...while loop 
    ' to enumerate the results before getting the next link.
    Do
        ' Write the page number.
        Console.WriteLine("Page {0}:", pageCount + 1)

        ' If nextLink is not null, then there is a new page to load.
        If token IsNot Nothing Then
            ' Load the new page from the next link URI.
            response = CType(context.Execute(Of Customer)(token),
            QueryOperationResponse(Of Customer))
        End If

        ' Enumerate the customers in the response.
        For Each customer As Customer In response
            Console.WriteLine(vbTab & "Customer Name: {0}", customer.CompanyName)
        Next

        ' Get the next link, and continue while there is a next link.
        token = response.GetContinuation()
    Loop While token IsNot Nothing
Catch ex As DataServiceQueryException
    Throw New ApplicationException(
            "An error occurred during query execution.", ex)
End Try

備註

此 Execute 方法用於透過 URI 查詢資料服務;此方法會向資料服務發出 HTTP GET 請求。 指定的請求 URI 可以是絕對的，也可以是相對的。

若 為 requestUri 絕對，此方法驗證 URI 是否指向建構 DataServiceContext時指定的相同資料服務。 若 為 requestUri 相對，此方法會去除所有前置斜線，並附加 requestUri 於構造 DataServiceContext時提供的斜線。 如果 URI 傳給 DataServiceContext 建構者，則會在 URI 上傳後加上斜線，若尚未存在。

當此方法回傳時，請求的所有 HTTP 回應都已從網路串流中讀取，但回應尚未被處理;沒有身份解析或物件的具體化。 在回應中指定的實體被枚舉前，不會對該實體進行身份解析與完整物件實體化。

另請參閱

• 載入延遲內容（WCF 資料服務）
• 如何：載入分頁結果（WCF Data Services）