The C # WebApi return Json

Find Global.asax file, add one in Application_Start () method:

protected void Application_Start() 
{ 
    AreaRegistration.RegisterAllAreas(); 
    WebApiConfig.Register(GlobalConfiguration.Configuration); 
    FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters); 
    RouteConfig.RegisterRoutes(RouteTable.Routes); 
    // 使api返回为json 
    GlobalConfiguration.Configuration.Formatters.XmlFormatter.SupportedMediaTypes.Clear(); 
}