portType绑定wsdl解析错误

Question

我在为soap服务创建wsdl文件时遇到问题。我在wsdl文件中声明了

<portType name="RegistrationService">
    <operation name="registration">
        <input message="tns:registration"/>
        <output message="tns:registrationResponse"/>
        <fault message="tns:ServerException" name="ServerException" />
        <fault message="tns:ValidationException" name="ValidationException" />
        <fault message="tns:DenialOfServiceException" name="DenialOfServiceException" />
    </operation>
</portType>

然后尝试像这样使用它

    <binding name="RegistrationBinding" type="tns:RegistrationService">
</binding>

但验证员抛弃了我

Could not find the portType definition for 'tns:RegistrationService' in the binding'RegistrationBinding'.

我无法弄清楚它有什么问题，因为我正在使用并正确调用它。