System.Web.Configuration.CompilationSection cmp = (System.Web.Configuration.CompilationSection)System.Configuration.ConfigurationManager.GetSection("system.web/compilation");
            if (!cmp.Debug)
            {
                filterContext.ExceptionHandled = true;
            }

这里有CompilationSection 类的介绍，微软官方的地址：

https://msdn.microsoft.com/zh-cn/library/system.web.configuration.compilationsection(v=vs.80).aspx