我怀疑您需要为webHttpBinding绑定添加绑定元素,并将maxReceivedMessageSize设置为较大的值。默认值为65536字节。

这需要在web.config的system.serviceModel节点中设置

下面是一个设置为5MB的xml示例

<bindings>
  <webHttpBinding>
    <binding name="largeMessage" maxReceivedMessageSize="5000000" maxBufferPoolSize="5000000" maxBufferSize="5000000" closeTimeout="00:03:00" openTimeout="00:03:00" receiveTimeout="00:10:00" sendTimeout="00:03:00">
      <readerQuotas maxStringContentLength="5000000" maxArrayLength="5000000" maxBytesPerRead="5000000" />
      <security mode="None"/>
    </binding>
  </webHttpBinding>
</bindings>

能否尝试更新服务节点以明确使用绑定配置(bindingConfiguration属性等于bindingName属性)。我不认为这是真的需要,因为只有一个绑定,但让我们尝试显式。

<services>
  <service name="ExamService.ExamService" behaviorConfiguration="serviceBehaviors">
    <endpoint address="" contract="ExamService.IExamService" binding="webHttpBinding" bindingConfiguration="largeMessage" behaviorConfiguration="web" ></endpoint>
  </service>
</services>

使现代化

namespace LargeMessageService
{
    [ServiceContract]
    public interface ILobService
    {

        [OperationContract]
        [WebGet]
        string EchoWithGet(string s);

        [OperationContract]
        [WebInvoke]
        string EchoWithPost(string s);
    }

    public class LobService : ILobService
    {
        public string EchoWithGet(string s)
        {
            return "You said " + s;
        }

        public string EchoWithPost(string s)
        {
            return "You said " + s;
        }
    }
}

当我有一个没有定义绑定的配置时,它以413失败,正如您所看到的。当我添加装订时,它起作用了。带绑定的完整web.config文件:

<appSettings>
  <add key="aspnet:UseTaskFriendlySynchronizationContext" value="true" />
</appSettings>
<system.web>
  <compilation debug="true" targetFramework="4.6.1" />
  <httpRuntime targetFramework="4.6.1"/>
</system.web>
<system.serviceModel>
  <behaviors>
    <serviceBehaviors>
      <behavior name="serviceBehaviors">
        <!-- To avoid disclosing metadata information, set the values below to false before deployment -->
        <serviceMetadata httpGetEnabled="true" />
        <!-- To receive exception details in faults for debugging purposes, set the value below to true.  Set to false before deployment to avoid disclosing exception information -->
        <serviceDebug includeExceptionDetailInFaults="true"/>
      </behavior>
    </serviceBehaviors>
    <endpointBehaviors>
      <behavior name="web" >
        <webHttp></webHttp>
      </behavior>
    </endpointBehaviors>
  </behaviors>
  <bindings>
    <webHttpBinding>
      <binding name="largeMessage" maxReceivedMessageSize="5000000" maxBufferPoolSize="5000000" maxBufferSize="5000000" closeTimeout="00:03:00" openTimeout="00:03:00" receiveTimeout="00:10:00" sendTimeout="00:03:00">
        <readerQuotas maxStringContentLength="5000000" maxArrayLength="5000000" maxBytesPerRead="5000000" />
        <security mode="None"/>
      </binding>
    </webHttpBinding>
  </bindings>
  <services>
    <service name="LargeMessageService.LobService" behaviorConfiguration="serviceBehaviors">
      <endpoint address="" contract="LargeMessageService.ILobService" binding="webHttpBinding" bindingConfiguration="largeMessage" behaviorConfiguration="web" ></endpoint>
      <endpoint contract="IMetadataExchange" binding="mexHttpBinding" address="mex" />
    </service>
  </services>
  <protocolMapping>
    <add binding="basicHttpsBinding" scheme="https"  />
  </protocolMapping>
  <serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true"/>
</system.serviceModel>
<system.webServer>
  <modules runAllManagedModulesForAllRequests="true"/>
  <!--
      To browse web app root directory during debugging, set the value below to true.
      Set to false before deployment to avoid disclosing web app folder information.
    -->
  <directoryBrowse enabled="true"/>
</system.webServer>

我使用IISExpress,通过Postman调用EchoWithPost操作,并使用xml调用它。

<string xmlns="http://schemas.microsoft.com/2003/10/Serialization/">Hello</string>

用大字符串替换“Hello”(约500K)

试着让这一个工作,如果它是一个案件,试图找出这一个和你的一个区别。让我知道你进展如何。