这是一个CORS问题，应从WCF服务端解决此问题，

It's a CORS issue, which should be fixed from the WCF service side,

首先，您必须在web.config上启用CORS

First you must enable CORS on web.config

<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>

OPTIONS请求，您必须以空响应答复，并添加您的应用程序类:

OPTIONS requests you must reply with empty response, adding in your application class:

protected void Application_BeginRequest()
{
    if (Request.Headers.AllKeys.Contains("Origin") && Request.HttpMethod == "OPTIONS")
    {
        Response.Flush();
    }
}