Question

如果wcf服务的设计方式如下，那么请指导我如何从客户端调用Add()函数Asynchronously。感谢

[ServiceContract]
public interface IAddTwoNumbers
{
    // If the asynchronous method pair
    // appears on the client channel, the client can call 
    // them asynchronously to prevent blocking.
    [OperationContract (AsyncPattern=true)]
    IAsyncResult BeginAdd(int a, int b, AsyncCallback cb, AsyncState s);

    [OperationContract]
    int EndAdd(IAsyncResult r);

    // This is a synchronous version of the BeginAdd/EndAdd pair.
    // It appears in the client channel code by default. 
    [OperationContract]
    int Add(int a, int b);
   }

Answer 1

我认为最好的方法是convert the APM pattern into the Task pattern，使用Task.Factory.FromAsync：

public static class WcfExt
{
    public static Task<int> AddAsync(this IAddTwoNumbers service, int a, int b)
    {
        return Task.Factory.FromAsync(
             (asyncCallback, asyncState) =>
                 service.BeginAdd(a, b, asyncCallback, asyncState),
             (asyncResult) =>
                 service.EndAdd(asyncResult), null);
    }
}

用法：

IAddTwoNumbers service = CreateWcfClientProxy();
int result = await service.AddAsync(a, b);

Answer 2

没有异步有线通信模式，WFC也不例外。通过电线进行异步需要对服务和合同进行根本性更改。具体而言，您的合同必须是双向合同，并且必须将“结束”从服务推送到客户端以及结果。换句话说，通过线路，'async'成为回调。

如何异步调用wcf服务

2 个答案: