从ActionFilterAttribute返回带有它的模型的视图

Question

在强类型视图上使用内置验证助手实现错误处理时,通常在控制器中创建一个try/catch块,并返回一个视图,其中相应的模型作为View()方法的参数:


控制器

public class MessageController : Controller
{
    [AcceptVerbs(HttpVerbs.Post)]
    public ActionResult Create(Models.Entities.Message message)
    {
        try
        {
            // Insert model into database
            var dc = new DataContext();
            dc.Messages.InsertOnSubmit(message);
            dc.SubmitChanges();

            return RedirectToAction("List");
        }
        catch
        {
            /* If insert fails, return a view with it's corresponding model to
               enable validation helpers */
            return View(message);
        }
    }
}

风景

<%@ Page
    Language="C#"
    Inherits="System.Web.Mvc.ViewPage<Models.Entities.Message>" %>

<%= Html.ValidationSummary("Fill out fields marked with *") %>

<% using (Html.BeginForm()) { %>

    <div><%= Html.TextBox("MessageText") %></div>

    <div><%= Html.ValidationMessage("MessageText", "*") %></div>

<% } %>

我已经以ActionFilterAttribute的形式实现了一个简单的错误处理程序,它可以重定向到一般错误视图,或者重定向到引发异常的视图,并让验证助手恢复生机.

以下是我的ActionFilterAttribute的外观:

public class ErrorLoggingAttribute : ActionFilterAttribute, IExceptionFilter
{
    private Boolean _onErrorRedirectToGenericErrorView;

    /// <param name="onErrorRedirectToGenericErrorView">
    /// True: redirect to a generic error view.
    /// False: redirect back the view which threw an exception
    /// </param>
    public ErrorLoggingAttribute(Boolean onErrorRedirectToGenericErrorView)
    {
        _onErrorRedirectToGenericErrorView = onErrorRedirectToGenericErrorView;
    }

    public void OnException(ExceptionContext ec)
    {
        if (_onErrorRedirectToGenericErrorView)
        {
            /* Redirect back to the view where the exception was thrown and
               include it's model so the validation helpers will work */
        }
        else
        {
            // Redirect to a generic error view
            ec.Result = new RedirectToRouteResult(new RouteValueDictionary
            {
                {"controller", "Error"},
                {"action", "Index"}
            });

            ec.ExceptionHandled = true;
        }
    }
}

重定向到抛出异常的视图非常简单.但这里是踢球者:为了使验证助手工作,你需要为视图提供它的模型.

你将如何返回抛出异常的视图并提供具有相应模型的视图？(在这种情况下Models.Entities.Message).

Answer 1

我得到了它的工作!

出于某种奇怪的原因,我需要做的就是将其传递ViewData给新的ResultView.

这是完整的代码:

public class ErrorLoggingAttribute : ActionFilterAttribute, IExceptionFilter
{
    private String _controllerName, _actionName;
    private Boolean _redirectToGenericView = false;


    public ErrorLoggingAttribute()
    {
    }


    public ErrorLoggingAttribute(String actionName, String controllerName)
    {
        _controllerName = controllerName;
        _actionName = actionName;
        _redirectToGenericView = true;
    }


    void IExceptionFilter.OnException(ExceptionContext ec)
    {
        // log error

        if (_redirectToGenericView)
        {
            ec.Result = new RedirectToRouteResult(new RouteValueDictionary
            {
                {"controller", _controllerName},
                {"action", _actionName}
            });
        }
        else
        {
            ec.Result = new ViewResult
            {
                ViewName = ((RouteData) ec.RouteData).Values["action"].ToString(),
                TempData = ec.Controller.TempData,
                ViewData = ec.Controller.ViewData
            };
        }

        ec.ExceptionHandled = true;
    }
}

用法

以下是如何在控制器操作上使用该属性,重定向到同一视图(使用它的关联模型),以便在发生异常时启用标准验证帮助程序:

[ErrorLogging]
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create(Models.Entities.Message message)
{
    var dc = new Models.DataContext();
    dc.Messages.InsertOnSubmit(message);
    dc.SubmitChanges();

    return RedirectToAction("List", new { id = message.MessageId });
}

以下是发生异常时如何使用该属性重定向到通用视图:

[ErrorLogging("ControllerName", "ViewName")]
[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Create(Models.Entities.Message message)

这是一个完全的逻辑分离.控制器中没有任何东西,但非常基础.