MVC WebAPI框架里设置异常返回格式统一

今天为了设置api返回格式统一，在网上找了一推资料，各种资料参差不齐的，最后自己捣鼓，终于弄出来了，直接上代码

/// <summary>
/// 消息代理处理，用来捕获这些特殊的异常信息
/// </summary>
public class CustomErrorMessageDelegatingHandler : DelegatingHandler
{
protected override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
return base.SendAsync(request, cancellationToken).ContinueWith<HttpResponseMessage>((responseToCompleteTask) =>
{
HttpResponseMessage response = responseToCompleteTask.Result;
HttpError error = null;
if (response.TryGetContentValue<HttpError>(out error))
{
//自定义错误处理
//error.Message = "这个接口调用出错了";
}
if (error != null)
{   //这是本人创建的一个返回类
var resultMsg = new ResultMsg { StatusCode = (int)StatusCodeEnum.HttpUrlEror, Info =error.MessageDetail  };
return new HttpResponseMessage { Content = new StringContent(resultMsg.ToJson(),
System.Text.Encoding.GetEncoding("UTF-8"), "application/json"), StatusCode = HttpStatusCode.OK };
}
else
{
return response;
}
});
}
}

protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
//FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
//RouteConfig.RegisterRoutes(RouteTable.Routes);
//BundleConfig.RegisterBundles(BundleTable.Bundles);
GlobalConfiguration.Configure(WebApiConfig.Register);
GlobalConfiguration.Configuration.Filters.Add(new ErrorHandler());
}

{
"StatusCode": 404,
"Info": "在控制器“StudyTask”上找不到与该请求匹配的操作。",
"Data": null
}