[英]There was an error while trying to serialize parameter http://tempuri.org/:callback
I have an asynchronous WCF server (I've derived my own clientbase class) and I call this from my client application. 我有一个异步WCF服务器(派生了自己的clientbase类),并从客户端应用程序中调用了它。
However, when this method is called: 但是,当调用此方法时:
public IAsyncResult Beginxxx(string path, AsyncCallback callback, object state)
{
return Channel.Beginxxx(path, callback, state);
}
I get this exception: 我得到这个例外:
{"There was an error while trying to serialize parameter http://tempuri.org/:callback . The InnerException message was 'Type 'System.DelegateSerializationHolder+DelegateEntry' with data contract name 'DelegateSerializationHolder.DelegateEntry:http://schemas.datacontract.org/2004/07/System' is not expected. Add any types not known statically to the list of known types - for example, by using the KnownTypeAttribute attribute or by adding them to the list of known types passed to DataContractSerializer.'. Please see InnerException for more details."}
{“尝试序列化参数http://tempuri.org/:callback时发生错误。InnerException消息是'Type'System.DelegateSerializationHolder + DelegateEntry',数据协定名称为'DelegateSerializationHolder.DelegateEntry:http:// schemas。 datacontract.org/2004/07/System'。将任何静态未知的类型添加到已知类型的列表中-例如,通过使用KnownTypeAttribute属性或将它们添加到传递给DataContractSerializer的已知类型的列表中。 。请参阅InnerException了解更多详细信息。“}
If I had my own class with its own properties, this exception would make sense but this is a standard .NET type (AsyncCallback I believe the exception is complaining about). 如果我有自己的具有自己属性的类,则此异常有意义,但这是标准的.NET类型(我相信该异常正在抱怨AsyncCallback)。 A code sample of what I am trying to do doesn't have this problem (and I changed that to the same type of binding I am using - named pipes).
我尝试执行的代码示例没有此问题(我将其更改为我正在使用的相同类型的绑定-命名管道)。
What is wrong? 怎么了?
You likely forgot to add the (AsyncPattern = true) property in the [OperationContract] attribute. 您可能忘记了在[OperationContract]属性中添加(AsyncPattern = true)属性。 The example below shows two clients, one (wrong) with the exact error you're seeing, one (correct) which works.
下面的示例显示了两个客户端,一个(错误)具有您看到的确切错误,一个(正确)有效。 The only difference is the AsyncPattern = true in the operation contract.
唯一的区别是操作协定中的AsyncPattern = true。
public class StackOverflow_5999249_751090
{
[ServiceContract(Name = "ITest", Namespace = "")]
public interface ITest
{
[OperationContract]
string Echo(string path);
}
public class Service : ITest
{
public string Echo(string path) { return path; }
}
[ServiceContract(Name = "ITest", Namespace = "")]
public interface ITestClient_Wrong
{
[OperationContract]
IAsyncResult BeginEcho(string path, AsyncCallback callback, object state);
string EndEcho(IAsyncResult asyncResult);
}
[ServiceContract(Name = "ITest", Namespace = "")]
public interface ITestClient_Correct
{
[OperationContract(AsyncPattern = true)]
IAsyncResult BeginEcho(string path, AsyncCallback callback, object state);
string EndEcho(IAsyncResult asyncResult);
}
static void PrintException(Exception e)
{
int indent = 2;
while (e != null)
{
for (int i = 0; i < indent; i++)
{
Console.Write(' ');
}
Console.WriteLine("{0}: {1}", e.GetType().FullName, e.Message);
indent += 2;
e = e.InnerException;
}
}
public static void Test()
{
string baseAddress = "net.pipe://localhost/Service";
ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
host.AddServiceEndpoint(typeof(ITest), new NetNamedPipeBinding(), "");
host.Open();
Console.WriteLine("Host opened");
AutoResetEvent evt = new AutoResetEvent(false);
Console.WriteLine("Correct");
ChannelFactory<ITestClient_Correct> factory1 = new ChannelFactory<ITestClient_Correct>(new NetNamedPipeBinding(), new EndpointAddress(baseAddress));
ITestClient_Correct proxy1 = factory1.CreateChannel();
proxy1.BeginEcho("Hello", delegate(IAsyncResult ar)
{
Console.WriteLine("Result from correct: {0}", proxy1.EndEcho(ar));
evt.Set();
}, null);
evt.WaitOne();
Console.WriteLine("Wrong");
ChannelFactory<ITestClient_Wrong> factory2 = new ChannelFactory<ITestClient_Wrong>(new NetNamedPipeBinding(), new EndpointAddress(baseAddress));
ITestClient_Wrong proxy2 = factory2.CreateChannel();
try
{
proxy2.BeginEcho("Hello", delegate(IAsyncResult ar)
{
try
{
Console.WriteLine("Result from wrong: {0}", proxy2.EndEcho(ar));
}
catch (Exception e)
{
PrintException(e);
}
evt.Set();
}, null);
evt.WaitOne();
}
catch (Exception e2)
{
PrintException(e2);
}
Console.WriteLine("Press ENTER to close");
Console.ReadLine();
host.Close();
}
}
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