Angular访问WebApi出现options方法

<!--解决optiongs方法-->
    <handlers>
      <remove name="ExtensionlessUrlHandler-Integrated-4.0" />
      <!--注释掉-->
      <!--<remove name="OPTIONSVerbHandler" />-->
      <remove name="TRACEVerbHandler" />
      <!--注释掉-->
      <!--<add name="ExtensionlessUrlHandler-Integrated-4.0" path="*." verb="*" type="System.Web.Handlers.TransferRequestHandler" preCondition="integratedMode,runtimeVersionv4.0" />-->
    </handlers>

<!--跨域-->
    <!--跨域-->
    <httpProtocol>
      <customHeaders>
        <add name="Access-Control-Allow-Origin" value="*" />
        <add name="Access-Control-Allow-Headers" value="Content-Type" />
        <add name="Access-Control-Allow-Methods" value="GET, POST, PUT, DELETE,OPTIONS" />
      </customHeaders>
    </httpProtocol>