尝试调用WCF Web服务4.0时获取返回类型无效错误

概述我正在尝试编写并调用WCF Web服务,下面是详细信息： Web.config文件： <add relativeAddress="FetchData.svc" service="WCF.Services.FetchData" /><service name="WCF.Services.FetchData"> <endpoint address="" binding="webHttpBi 我正在尝试编写并调用WCF Web服务,下面是详细信息：

Web.config文件：

<add relativeAddress="FetchData.svc" service="WCF.Services.FetchData" /><service name="WCF.Services.FetchData">    <endpoint address="" binding="webhttpBinding" bindingConfiguration="" name="FetchData" contract="WCF.Services.FetchData" /></service>

FetchData类(示例代码)：

using System;using System.Collections.Generic;using System.linq;using System.ServiceModel;using System.ServiceModel.Activation;using System.Web;using System.Xml;using Webservices.Services;using Data = Webservices.Data;using System.ServiceModel.Web;using System.IO;using System.Net;using System.ServiceModel.Channels;using System.Web.UI;using System.Text;namespace WCF.Services{        [ServiceContract(namespace = "urn:WCF.Services.FetchData")]    public class FetchData    {        Data.GetConnect mConnect = new Data.GetConnect();        private Message RetrIEvePublishedData(String pub,int number)        {            String strOutput = String.Empty;             if (!String.IsNullOrEmpty(pub))            {                Boolean pubURLExists = mConnect.CheckPubUrlExists(pub);                if (!pubURLExists)                {                    WebOperationContext.Current.OutgoingResponse.StatusCode = httpStatusCode.NotFound;                    return WebOperationContext.Current.CreateTextResponse(String.Format("Requested publication '{0}' is not available.",pub),MimeTypes.TextPlain,EnCoding.UTF8);                }                using (StringWriter sw = new StringWriterEnCoding())                {                    using (HTMLTextWriter hw = new HTMLTextWriter(sw))                    {                        hw.RenderBeginTag(HTMLTextWriterTag.HTML);                        XmlNode publishedData = mConnect.GetPublishedData(pub,number);                        hw.RenderEndTag();                    }                    return WebOperationContext.Current.CreateTextResponse(sw.ToString(),MimeTypes.TextHTML,EnCoding.UTF8);                }            }            return WebOperationContext.Current.CreateTextResponse(strOutput,EnCoding.UTF8);        }        [OperationContract]        [WebGet(UriTemplate = "/published/{number}/{*pub=default}")]        public Message FetchPublished(String pub,int number)        {           return RetrIEvePublishedData(pub,number);        }    }}

现在,当我尝试浏览Web服务时,我收到以下错误：

Web服务URL – http：// localhost：8082 / FetchData.svc

错误：
无法加载“FetchPublished” *** 作,因为它具有System.ServiceModel.Channels.Message类型的参数或返回类型,或者具有MessageContractAttribute的类型和其他不同类型的参数.使用System.ServiceModel.Channels.Message或使用MessageContractAttribute类型时,该方法不得使用任何其他类型的参数.

编辑：

namespace WCFWebServices{    [ServiceBehavior(AddressFilterMode = AddressFilterMode.Any)]     [ServiceContract(namespace = "urn:WCFWebServices.fetchPush")]        public class FetchData        {         [MessageContract]         public class RetrIEvePublishedDatainput         {             [MessageBodyMember]             public String pub;             [MessageBodyMember]             public String number;         }            private Message RetrIEvePublishedData(RetrIEvePublishedDatainput input)            {                String strOutput = String.Empty;                String pub = input.pub;                String number = input.number;                if (!String.IsNullOrEmpty(pub))                {                    Boolean pubURLExists = true;                    if (!pubURLExists)                    {                        WebOperationContext.Current.OutgoingResponse.StatusCode = httpStatusCode.NotFound;                        return WebOperationContext.Current.CreateTextResponse(String.Format("Requested publication '{0}' is not available.","application/plain; charset=utf-8",EnCoding.UTF8);                    }                    using (StringWriter sw = new StringWriter())                    {                        using (HTMLTextWriter hw = new HTMLTextWriter(sw))                        {                            hw.RenderBeginTag(HTMLTextWriterTag.HTML);                            hw.RenderEndTag();                        }                        return WebOperationContext.Current.CreateTextResponse(sw.ToString(),"application/HTML; charset=utf-8",EnCoding.UTF8);                    }                }                return WebOperationContext.Current.CreateTextResponse(strOutput,EnCoding.UTF8);            }            [OperationContract]            [WebGet(UriTemplate = "/publishedData/{number}/{pub=default}")]            public Message FetchPublished(RetrIEvePublishedDatainput input)            {                return RetrIEvePublishedData(input);            }        }      }

解决方法 我相信提到的错误是非常自我解释的.根据 the MSDN,使用Message类有自己的限制：

You can use the Message class as an input parameter of an operation,the return value of an operation,or both. If Message is used anywhere in an operation,the following restrictions apply:

The operation cannot have any out or ref parameters. There cannot be more than one input parameter. If the parameter is present,it must be either Message or a message contract type. The return type must be either voID,Message,or a message contract type.

如果是您的合同,则违反第二个限制.最简单的解决方法是创建适当的MessageContract：

[MessageContract]public class RetrIEvePublishedDatainput{  [MessageBodyMember] public string Pub;  [MessageBodyMember] public int Number;}private Message RetrIEvePublishedData(RetrIEvePublishedDatainput input){    ....}

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