如何使用通道工厂异步调用操作

本主题介绍客户端在使用基于ChannelFactory<TChannel>的客户端应用程序时如何异步访问服务操作。（使用 System.ServiceModel.ClientBase<TChannel> 对象调用服务时，可以使用事件驱动的异步调用模型。有关详细信息，请参阅如何：异步调用服务操作。有关基于事件的异步调用模型的详细信息，请参阅基于事件的异步模式（EAP）。）

本主题中的服务实现 ICalculator 接口。客户端可以异步调用此接口上的操作，这意味着类似 Add 的操作被拆分为两种方法，前者 BeginAdd 启动调用，而后者 EndAdd 在操作完成时检索结果。有关如何在服务中异步实现作的示例，请参阅如何：实现异步服务作。有关同步和异步作的详细信息，请参阅同步和异步作。

Procedure

异步调用 WCF 服务操作

使用以下命令中所示的选项运行 /async 工具。

svcutil /n:http://Microsoft.ServiceModel.Samples,Microsoft.ServiceModel.Samples http://localhost:8000/servicemodelsamples/service/mex /a

这会为操作生成服务契约的异步客户端版本。

创建在异步作完成时要调用的回调函数，如以下示例代码所示。

static void AddCallback(IAsyncResult ar)
{
    double result = ((CalculatorClient)ar.AsyncState).EndAdd(ar);
    Console.WriteLine($"Add Result: {result}");
}

Private Shared Sub AddCallback(ByVal ar As IAsyncResult)
    Dim result = (CType(ar.AsyncState, CalculatorClient)).EndAdd(ar)
    Console.WriteLine("Add Result: {0}", result)
End Sub

若要异步访问服务作，请创建客户端并调用 Begin[Operation] （例如 BeginAdd），并指定回调函数，如以下示例代码所示。

ChannelFactory<ICalculatorChannel> factory = new ChannelFactory<ICalculatorChannel>();
ICalculatorChannel channelClient = factory.CreateChannel();

// BeginAdd
double value1 = 100.00D;
double value2 = 15.99D;

IAsyncResult arAdd = channelClient.BeginAdd(value1, value2, AddCallback, channelClient);
Console.WriteLine($"Add({value1},{value2})");

Dim factory As New ChannelFactory(Of ICalculatorChannel)()
Dim channelClient As ICalculatorChannel = factory.CreateChannel()

' BeginAdd
Dim value1 = 100.0R
Dim value2 = 15.99R

Dim arAdd As IAsyncResult = channelClient.BeginAdd(value1, value2, AddressOf AddCallback, channelClient)
Console.WriteLine("Add({0},{1})", value1, value2)

执行回调函数时，客户端将调用 End<operation> （例如）， EndAdd以检索结果。

Example

与上述过程中使用的客户端代码一起使用的服务实现 ICalculator 接口，如以下代码所示。在服务端，AddSubtract合约的操作由 Windows Communication Foundation（WCF）在运行时同步调用，即使在之前的客户端步骤是异步调用的。 Multiply和Divide操作用于在服务端异步调用服务，即使客户端同步调用服务也是如此。本示例将 AsyncPattern 属性设置为 true. 此属性设置与 .NET Framework 异步模式的实现相结合，告知运行时异步调用操作。

[ServiceContract(Namespace = "http://Microsoft.ServiceModel.Samples")]
public interface ICalculator
{
    [OperationContract]
    double Add(double n1, double n2);

    [OperationContract]
    double Subtract(double n1, double n2);

    //Multiply involves some file I/O so we'll make it Async.
    [OperationContract(AsyncPattern = true)]
    IAsyncResult BeginMultiply(double n1, double n2, AsyncCallback callback, object state);
    double EndMultiply(IAsyncResult ar);

    //Divide involves some file I/O so we'll make it Async.
    [OperationContract(AsyncPattern = true)]
    IAsyncResult BeginDivide(double n1, double n2, AsyncCallback callback, object state);
    double EndDivide(IAsyncResult ar);
}

<ServiceContract(Namespace:="http://Microsoft.ServiceModel.Samples")> _
Public Interface ICalculator
    <OperationContract> _
    Function Add(ByVal n1 As Double, ByVal n2 As Double) As Double

    <OperationContract> _
    Function Subtract(ByVal n1 As Double, ByVal n2 As Double) As Double

    'Multiply involves some file I/O so we'll make it Async.
    <OperationContract(AsyncPattern:=True)> _
    Function BeginMultiply(ByVal n1 As Double, ByVal n2 As Double, ByVal callback As AsyncCallback, ByVal state As Object) As IAsyncResult
    Function EndMultiply(ByVal ar As IAsyncResult) As Double

    'Divide involves some file I/O so we'll make it Async.
    <OperationContract(AsyncPattern:=True)> _
    Function BeginDivide(ByVal n1 As Double, ByVal n2 As Double, ByVal callback As AsyncCallback, ByVal state As Object) As IAsyncResult
    Function EndDivide(ByVal ar As IAsyncResult) As Double
End Interface

Last updated on 2025-12-03

通过

如何使用通道工厂异步调用操作

Procedure

异步调用 WCF 服务操作

Example

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