为什么WCF异步方法中有Response返回类型？

Question

I am not so perfect in WCF and still a learner. The place where I learnt WCF services taught me that WCF service Async method also return the same datatype as of the original method. It was working fine on the project I downloaded but with same configuration I created a new project and its not returning the original method's data type. Instead a response type like:

As you can see its showing isEmailExistsResponse type. How can I make it to return bool type?

My Configuration

Client Side:

<system.serviceModel>
    <bindings>
      <basicHttpBinding>
        <binding name="BasicHttpBinding_IService1"/>
      </basicHttpBinding>
    </bindings>
    <client>
      <endpoint address="http://localhost/Service1.svc" binding="basicHttpBinding" bindingConfiguration="BasicHttpBinding_IService1" contract="WCORE.IService1" name="BasicHttpBinding_IService1"/>
    </client>
  </system.serviceModel>

Server side:

<system.serviceModel>
    <behaviors>
      <serviceBehaviors>
        <behavior>
          <!-- To avoid disclosing metadata information, set the values below to false before deployment -->
          <serviceMetadata httpGetEnabled="true" httpsGetEnabled="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>
    </behaviors>
    <protocolMapping>
      <add binding="basicHttpsBinding" scheme="https"/>
    </protocolMapping>
    <serviceHostingEnvironment aspNetCompatibilityEnabled="true" multipleSiteBindingsEnabled="true"/>
  </system.serviceModel>

I am using .NET 4.5 on both client and service. But my server is installed with 4.0. So I may switch to 4.0 if service encountered some problem on final deployment.

WCF Client Settings:

Answer 1

You need to await the Async method:

var isEmailExists = await client.isEmailsExistsAsync(email);
if (isEmailExists == false) {
...
}

Answer 2

Wherever you see a return type of Task<SomeOtherType> you will have to use the new await keyword to handle it property.

http://msdn.microsoft.com/en-us/library/vstudio/hh191443.aspx