Ionic 2 CROS

I not able to use WCF services in ionic app.
It gives me CROS origine error,means block by services.
Even we have give all the paramater in our wcf services like as follows

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

pl provide us solution.We are not able work on app our work is stuck so that we can use WCF services in our app

waiting for your response