使C# WebApi返回Json

找到Global.asax文件，在Application_Start()方法中添加一句：

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();
}