我正在尝试实现WCF回调。当我在服务端调用回调方法时,它会异步执行。有没有一种方法可以在服务方法进入下一条语句之前等待回调方法完成执行,而不从回调中向服务返回值?
//Server Side
public interface ICallback
{
[OperationContract]
void Oncallback1(string str);
[OperationContract]
int Oncallback2(string str);
}
[ServiceContract(CallbackContract = typeof(ICallback))]
public interface IServiceContract
{
[OperationContract]
void Method1();
}
[ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Reentrant)]
public class MycallbackService : IServiceContract
{
public void Method1()
{
ICallback objIcallback = OperationContext.Current.GetCallbackChannel<ICallback>();
Thread.Sleep(5000);
objIcallback.Oncallback1(obj1);
Console.WriteLine("calling callback2");
Console.WriteLine(objIcallback.Oncallback2("2"));
Console.WriteLine("Service Execution over!");
}
}
//Client Side
[CallbackBehavior]
public class callbackClient : ICallback
{
public void Oncallback1(CallbackService.EventInfo obj)
{
Thread.Sleep(5000);
Console.WriteLine("Callback 1");
}
public int Oncallback2(string str)
{
Thread.Sleep(5000);
Console.WriteLine("Callback 4");
return 2;
}
}
在这里,语句"Console.WriteLine("callback2");"在callback1方法完成之前执行。而它则等待回调2完成。
我相信这是因为回调方法的返回类型不同:
void Oncallback1(string str);
int Oncallback2(string str);
Oncallback1
不返回任何内容,因此默认情况下它是IsOneWay = true
即发即弃操作。另一方面,Oncallback2
默认为IsOneWay = false