我有WCF服务，它可以以List＆lt; List＆lt; object＆gt;＆gt;的形式接受和返回相当大量的数据。我的问题是典型行的输出如下所示：
<d:ArrayOfanyType>
<d:anyType i:type="e:string" xmlns:e="http://www.w3.org/2001/XMLSchema">PJ123</d:anyType>
<d:anyType i:type="e:double" xmlns:e="http://www.w3.org/2001/XMLSchema">2</d:anyType>
<d:anyType i:type="e:string" xmlns:e="http://www.w3.org/2001/XMLSchema">216565</d:anyType>
<d:anyType i:type="e:dateTime" xmlns:e="http://www.w3.org/2001/XMLSchema">1993-09-10T00:00:00</d:anyType>
<d:anyType i:type="e:string" xmlns:e="http://www.w3.org/2001/XMLSchema">Timesheet W/E 11/9/93 Franklin</d:anyType>
<d:anyType i:type="e:string" xmlns:e="http://www.w3.org/2001/XMLSchema">CONSULT OF</d:anyType>
<d:anyType i:type="e:double" xmlns:e="http://www.w3.org/2001/XMLSchema">25</d:anyType>
<d:anyType i:type="e:double" xmlns:e="http://www.w3.org/2001/XMLSchema">0</d:anyType>
<d:anyType i:type="e:double" xmlns:e="http://www.w3.org/2001/XMLSchema">25</d:anyType>
</d:ArrayOfanyType>
因此每行中的每个值都定义了“e”命名空间，这大大增加了消息的大小。我知道这背后的原因是DataContractSerializer不必进行2次通过，但是以更大的消息大小为代价获得一点处理性能似乎很容易。我已经考虑过如何更改数据结构，但字段确实可以是任何内容，我无法避免使用<anyType>元素。
有没有人知道拦截WCF管道并删除/重新组织这些命名空间声明的方法？
答案 0 :(得分：2)
您可以使用自定义编码器执行此操作 - 此时您可以根据需要使用XML。正如John Saunders所指出的那样，这将导致（可能是重大的）性能损失，但它确实有效。下面的代码显示了您将如何处理它。
public class StackOverflow_6681219
{
[ServiceContract]
public interface ITest
{
[OperationContract]
List<List<object>> GetData();
}
public class Service : ITest
{
public List<List<object>> GetData()
{
return new List<List<object>>
{
new List<object>
{
"PJ123",
2.0,
"216565",
new DateTime(1993, 9, 10),
"Timesheet W/E 11/9/93 Franklin",
"CONSULT OF",
25.0,
0.0,
25.0
}
};
}
}
class MyEncodingBindingElement : MessageEncodingBindingElement
{
MessageEncodingBindingElement inner;
public MyEncodingBindingElement(MessageEncodingBindingElement inner)
{
this.inner = inner;
}
public override MessageEncoderFactory CreateMessageEncoderFactory()
{
return new MyEncoderFactory(this.inner.CreateMessageEncoderFactory());
}
public override MessageVersion MessageVersion
{
get { return this.inner.MessageVersion; }
set { this.inner.MessageVersion = value; }
}
public override BindingElement Clone()
{
return new MyEncodingBindingElement(this.inner);
}
public override bool CanBuildChannelListener<TChannel>(BindingContext context)
{
return context.CanBuildInnerChannelListener<TChannel>();
}
public override IChannelListener<TChannel> BuildChannelListener<TChannel>(BindingContext context)
{
context.BindingParameters.Add(this);
return context.BuildInnerChannelListener<TChannel>();
}
class MyEncoderFactory : MessageEncoderFactory
{
MessageEncoderFactory inner;
public MyEncoderFactory(MessageEncoderFactory inner)
{
this.inner = inner;
}
public override MessageEncoder Encoder
{
get { return new MyEncoder(this.inner.Encoder); }
}
public override MessageVersion MessageVersion
{
get { return this.inner.MessageVersion; }
}
}
class MyEncoder : MessageEncoder
{
MessageEncoder inner;
public MyEncoder(MessageEncoder inner)
{
this.inner = inner;
}
public override string ContentType
{
get { return this.inner.ContentType; }
}
public override string MediaType
{
get { return this.inner.MediaType; }
}
public override bool IsContentTypeSupported(string contentType)
{
return this.inner.IsContentTypeSupported(contentType);
}
public override MessageVersion MessageVersion
{
get { return this.inner.MessageVersion; }
}
public override Message ReadMessage(ArraySegment<byte> buffer, BufferManager bufferManager, string contentType)
{
return this.inner.ReadMessage(buffer, bufferManager, contentType);
}
public override Message ReadMessage(Stream stream, int maxSizeOfHeaders, string contentType)
{
throw new NotImplementedException();
}
public override ArraySegment<byte> WriteMessage(Message message, int maxMessageSize, BufferManager bufferManager, int messageOffset)
{
const string XmlnsNamespace = "http://www.w3.org/2000/xmlns/";
const string SchemaNamespace = "http://www.w3.org/2001/XMLSchema";
const string ArraysNamespace = "http://schemas.microsoft.com/2003/10/Serialization/Arrays";
const string SchemaInstanceNamespace = "http://www.w3.org/2001/XMLSchema-instance";
ArraySegment<byte> temp = this.inner.WriteMessage(message, maxMessageSize, bufferManager, messageOffset);
MemoryStream ms = new MemoryStream(temp.Array, temp.Offset, temp.Count);
XmlDocument doc = new XmlDocument();
doc.Load(ms);
bufferManager.ReturnBuffer(temp.Array);
XmlAttribute rootAttr = doc.CreateAttribute("xmlns", "sch", XmlnsNamespace);
rootAttr.Value = SchemaNamespace;
doc.DocumentElement.Attributes.Append(rootAttr);
XmlNamespaceManager nsManager = new XmlNamespaceManager(doc.NameTable);
nsManager.AddNamespace("arrays", ArraysNamespace);
foreach (XmlNode arrayItem in doc.SelectNodes("//arrays:anyType", nsManager))
{
XmlAttribute toRemove = null;
XmlAttribute typeAttr = null;
foreach (XmlAttribute attr in arrayItem.Attributes)
{
if (attr.Prefix == "xmlns" && attr.Value == SchemaNamespace)
{
toRemove = attr;
}
else if (attr.LocalName == "type" && attr.NamespaceURI == SchemaInstanceNamespace)
{
typeAttr = attr;
}
}
if (toRemove != null)
{
arrayItem.Attributes.Remove(toRemove);
if (typeAttr != null)
{
string prefix = toRemove.LocalName;
typeAttr.Value = typeAttr.Value.Replace(prefix + ":", "sch:");
}
}
}
ms = new MemoryStream();
doc.Save(ms);
byte[] buffer = bufferManager.TakeBuffer((int)ms.Length + messageOffset);
Array.Copy(ms.GetBuffer(), 0, buffer, messageOffset, (int)ms.Length);
return new ArraySegment<byte>(buffer, messageOffset, (int)ms.Length);
}
public override void WriteMessage(Message message, Stream stream)
{
throw new NotImplementedException();
}
}
}
static Binding ReplaceEncoding(Binding original)
{
CustomBinding custom = new CustomBinding(original);
for (int i = 0; i < custom.Elements.Count; i++)
{
MessageEncodingBindingElement mebe = custom.Elements[i] as MessageEncodingBindingElement;
if (mebe != null)
{
custom.Elements[i] = new MyEncodingBindingElement(mebe);
break;
}
}
return custom;
}
public static void Test()
{
string baseAddress = "http://" + Environment.MachineName + ":8000/Service";
ServiceHost host = new ServiceHost(typeof(Service), new Uri(baseAddress));
Binding binding = ReplaceEncoding(new BasicHttpBinding());
host.AddServiceEndpoint(typeof(ITest), binding, "");
host.Open();
Console.WriteLine("Host opened");
ChannelFactory<ITest> factory = new ChannelFactory<ITest>(new BasicHttpBinding(), new EndpointAddress(baseAddress));
ITest proxy = factory.CreateChannel();
Console.WriteLine(proxy.GetData());
((IClientChannel)proxy).Close();
factory.Close();
Console.Write("Press ENTER to close the host");
Console.ReadLine();
host.Close();
}
}