Asp.net mvc 在ASP.NET MVC中，如何重构try/catch并返回JSON错误消息？

如何最好地在新的ASP.NET MVC应用程序中创建基本控制器，该应用程序将包含样板代码，以处理派生控制器中每个操作的所有try/catch例程，并在登录到Nlog后返回标准JSON错误消息。我还想处理404错误以重定向到自定义404视图。我的目标是使用OWIN cookie身份验证，并希望在cookie过期时注销。我的所有操作都将返回JsonResult并通过jQueryAjax调用

在以前的项目中，我使用了以下方法：

在

Global.asax.cs中

  protected void Application_Error(object sender, EventArgs e)
    {
        Exception lastError = Server.GetLastError();
        Server.ClearError();

        var statusCode = 0;

        statusCode = lastError.GetType() == typeof(HttpException) ? ((HttpException)lastError).GetHttpCode() : 500;

        var routeData = new RouteData();
        routeData.Values.Add("controller", "Error");
        routeData.Values.Add("statusCode", statusCode);
        routeData.Values.Add("exception", lastError);

        if (new HttpRequestWrapper(HttpContext.Current.Request).IsAjaxRequest())
        {
            routeData.Values.Add("action", "Ajax");     
        }
        else
        {
            routeData.Values.Add("action", "Index");
        }

        var requestContext = new RequestContext(new HttpContextWrapper(Context), routeData);

        IController controller = new ErrorController();
        controller.Execute(requestContext);

        Response.End();
    }

 public class ErrorController : Controller
{
    public ActionResult Index(int statusCode, Exception exception)
    {
        var model = new ErrorModel { HttpStatusCode = statusCode, Exception = exception.Message };

        Response.StatusCode = statusCode;

        return View(model);
    }

    public JsonResult Ajax(int statusCode, Exception exception, Dictionary<string,string> validationErrors = null)
    {
        var model = new ErrorModel { HttpStatusCode = statusCode, Exception = exception.Message };

        if (exception.GetType() == typeof (DbEntityValidationException))
        {
            model.ValidationErrors = null;
        }
        else
        {
            model.ValidationErrors = validationErrors;
        }

        Response.StatusCode = statusCode;

        return Json(model, JsonRequestBehavior.AllowGet);
    }
}

在

ErrorController.cs中

  protected void Application_Error(object sender, EventArgs e)
    {
        Exception lastError = Server.GetLastError();
        Server.ClearError();

        var statusCode = 0;

        statusCode = lastError.GetType() == typeof(HttpException) ? ((HttpException)lastError).GetHttpCode() : 500;

        var routeData = new RouteData();
        routeData.Values.Add("controller", "Error");
        routeData.Values.Add("statusCode", statusCode);
        routeData.Values.Add("exception", lastError);

        if (new HttpRequestWrapper(HttpContext.Current.Request).IsAjaxRequest())
        {
            routeData.Values.Add("action", "Ajax");     
        }
        else
        {
            routeData.Values.Add("action", "Index");
        }

        var requestContext = new RequestContext(new HttpContextWrapper(Context), routeData);

        IController controller = new ErrorController();
        controller.Execute(requestContext);

        Response.End();
    }

 public class ErrorController : Controller
{
    public ActionResult Index(int statusCode, Exception exception)
    {
        var model = new ErrorModel { HttpStatusCode = statusCode, Exception = exception.Message };

        Response.StatusCode = statusCode;

        return View(model);
    }

    public JsonResult Ajax(int statusCode, Exception exception, Dictionary<string,string> validationErrors = null)
    {
        var model = new ErrorModel { HttpStatusCode = statusCode, Exception = exception.Message };

        if (exception.GetType() == typeof (DbEntityValidationException))
        {
            model.ValidationErrors = null;
        }
        else
        {
            model.ValidationErrors = validationErrors;
        }

        Response.StatusCode = statusCode;

        return Json(model, JsonRequestBehavior.AllowGet);
    }
}

公共类错误控制器：控制器
{
公共操作结果索引（int状态代码、异常）
{
var model=newerrormodel{HttpStatusCode=statusCode，Exception=Exception.Message}；
Response.StatusCode=状态码；
返回视图（模型）；
}
公共JsonResult Ajax（int状态码、异常、字典验证错误=null）
{
var model=newerrormodel{HttpStatusCode=statusCode，Exception=Exception.Message}；
if（exception.GetType（）==typeof（DbEntityValidationException））
{
model.ValidationErrors=null；
}
其他的
{
model.ValidationErrors=ValidationErrors；
}
Response.StatusCode=状态码；
返回Json（model，JsonRequestBehavior.AllowGet）；
}
}

最好的方法是扩展

HandleErrorAttribute

如下：

public class AjaxAwareHandleErrorAttribute : HandleErrorAttribute
{
    public override void OnException(ExceptionContext filterContext)
    {
        // Execute the normal exception handling routine...
        base.OnException(filterContext);            

        // Verify if AJAX request...
        if (filterContext.HttpContext.Request.IsAjaxRequest())
        {
            // Use Json in case of AJAX request...
            var result = new JsonResult();                
            result.Data = new { Error = filterContext.Exception.Message };

            filterContext.Result = result;
        }
    }
}

public class FilterConfig
{
    public static void RegisterGlobalFilters(GlobalFilterCollection filters)
    {
        filters.Add(new AjaxAwareHandleErrorAttribute());
    }
}

然后，您只需在

App\u Start

文件夹下的

FilterConfig

类中注册该属性，如下所示：

public class AjaxAwareHandleErrorAttribute : HandleErrorAttribute
{
    public override void OnException(ExceptionContext filterContext)
    {
        // Execute the normal exception handling routine...
        base.OnException(filterContext);            

        // Verify if AJAX request...
        if (filterContext.HttpContext.Request.IsAjaxRequest())
        {
            // Use Json in case of AJAX request...
            var result = new JsonResult();                
            result.Data = new { Error = filterContext.Exception.Message };

            filterContext.Result = result;
        }
    }
}

public class FilterConfig
{
    public static void RegisterGlobalFilters(GlobalFilterCollection filters)
    {
        filters.Add(new AjaxAwareHandleErrorAttribute());
    }
}