DataServiceContext.ExecuteBatch(DataServiceRequest[]) 方法

public:
 System::Data::Services::Client::DataServiceResponse ^ ExecuteBatch(... cli::array <System::Data::Services::Client::DataServiceRequest ^> ^ queries);

public System.Data.Services.Client.DataServiceResponse ExecuteBatch(params System.Data.Services.Client.DataServiceRequest[] queries);

member this.ExecuteBatch : System.Data.Services.Client.DataServiceRequest[] -> System.Data.Services.Client.DataServiceResponse

Public Function ExecuteBatch (ParamArray queries As DataServiceRequest()) As DataServiceResponse

参数

返回

对批处理操作的响应。

示例

以下示例演示如何调用ExecuteBatch该方法以执行包含从 Northwind 数据服务返回和DataServiceRequest<TElement>Customers对象的查询的对象数组Products。 枚举返回QueryOperationResponse<T>的对象集合DataServiceResponse，同时枚举每个QueryOperationResponse<T>对象中包含的对象集合。 此示例使用 DataServiceContext 基于 Northwind 数据服务生成的“添加服务引用”工具，该工具是在完成 WCF 数据服务时创建的。

string customerId = "ALFKI";

// Create the DataServiceContext using the service URI.
NorthwindEntities context = new NorthwindEntities(svcUri);

// Create the separate query URI's, one that returns
// a single customer and another that returns all Products.
Uri customerUri = new Uri(svcUri.AbsoluteUri +
    "/Customers('" + customerId + "')/?$expand=Orders");
Uri productsUri = new Uri(svcUri.AbsoluteUri +
   "/Products");

// Create the query requests.
DataServiceRequest<Customer> customerQuery =
    new DataServiceRequest<Customer>(customerUri);
DataServiceRequest<Product> productsQuery =
                new DataServiceRequest<Product>(productsUri);

// Add the query requests to a batch request array.
DataServiceRequest[] batchRequests =
    new DataServiceRequest[]{customerQuery, productsQuery};

DataServiceResponse batchResponse;

try
{
    // Execute the query batch and get the response.
    batchResponse = context.ExecuteBatch(batchRequests);

    if (batchResponse.IsBatchResponse)
    {
        // Parse the batchResponse.BatchHeaders.
    }
    // Enumerate over the results of the query.
    foreach (QueryOperationResponse response in batchResponse)
    {
        // Handle an error response.
        if (response.StatusCode > 299 || response.StatusCode < 200)
        {
            Console.WriteLine("An error occurred.");
            Console.WriteLine(response.Error.Message);
        }
        else
        {
            // Find the response for the Customers query.
            if (response.Query.ElementType == typeof(Customer))
            {
                foreach (Customer customer in response)
                {
                    Console.WriteLine("Customer: {0}", customer.CompanyName);
                    foreach (Order order in customer.Orders)
                    {
                        Console.WriteLine("Order ID: {0} - Freight: {1}",
                            order.OrderID, order.Freight);
                    }
                }
            }
            // Find the response for the Products query.
            else if (response.Query.ElementType == typeof(Product))
            {
                foreach (Product product in response)
                {
                    Console.WriteLine("Product: {0}", product.ProductName);
                }
            }
        }
    }
}

// This type of error is raised when the data service returns with
// a response code < 200 or >299 in the top level element.
catch (DataServiceRequestException e)
{
    // Get the response from the exception.
    batchResponse = e.Response;

    if (batchResponse.IsBatchResponse)
    {
        // Parse the batchResponse.BatchHeaders.
    }

    foreach (QueryOperationResponse response in batchResponse)
    {
        if (response.Error != null)
        {
            Console.WriteLine("An error occurred.");
            Console.WriteLine(response.Error.Message);
        }
    }
}

Dim customerId = "ALFKI"

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

' Create the separate query URI's, one that returns 
' a single customer and another that returns all Products.
Dim customerUri = New Uri(svcUri.AbsoluteUri &
    "/Customers('" & customerId & "')/?$expand=Orders")
Dim productsUri = New Uri(svcUri.AbsoluteUri &
       "/Products")

' Create the query requests.
Dim customerQuery = New DataServiceRequest(Of Customer)(customerUri)
Dim productsQuery = New DataServiceRequest(Of Product)(productsUri)

' Add the query requests to a batch request array.
Dim batchRequests =
    New DataServiceRequest() {customerQuery, productsQuery}

Dim batchResponse As DataServiceResponse

Try
    ' Execute the query batch and get the response.
    batchResponse = context.ExecuteBatch(batchRequests)

    If batchResponse.IsBatchResponse Then
        ' Parse the batchResponse.BatchHeaders.
    End If

    ' Enumerate over the results of the query.
    For Each response As QueryOperationResponse In batchResponse
        ' Handle an error response.
        If response.StatusCode > 299 OrElse response.StatusCode < 200 Then
            Console.WriteLine("An error occurred.")
            Console.WriteLine(response.Error.Message)
        Else
            ' Find the response for the Customers query.
            If response.Query.ElementType Is GetType(Customer) Then
                For Each customer As Customer In response
                    Console.WriteLine("Customer: {0}", customer.CompanyName)
                    For Each order As Order In customer.Orders
                        Console.WriteLine("Order ID: {0} - Freight: {1}",
                                order.OrderID, order.Freight)
                    Next
                Next
                ' Find the response for the Products query.
            ElseIf response.Query.ElementType Is GetType(Product) Then
                For Each product As Product In response
                    Console.WriteLine("Product: {0}", product.ProductName)
                Next
            End If
        End If
    Next
    ' This type of error is raised when the data service returns with
    ' a response code < 200 or >299 in the top level element.
Catch ex As DataServiceRequestException
    ' Get the response from the exception.
    batchResponse = ex.Response

    If (batchResponse.IsBatchResponse) Then
        ' Parse the batchResponse.BatchHeaders.
    End If
    For Each response As QueryOperationResponse In batchResponse
        If response.Error IsNot Nothing Then
            Console.WriteLine("An error occurred.")
            Console.WriteLine(response.Error.Message)
        End If
    Next
End Try

注解

查询指定为 DataServiceRequest<TElement> 实例。 返回一个 DataServiceResponse 代表整个批处理请求的响应。 单个查询响应表示为可通过枚举实例访问的OperationResponse单个DataServiceResponse对象。

此方法从网络流中读取批处理请求的整个 HTTP 响应时，但尚未处理响应。 在枚举指定实体之前，响应中不会发生标识解析或对象具体化。

另请参阅

• 如何：在批处理中执行查询（WCF 数据服务）