如何将模型传递给具有其他参数的动作

Question

我的以下问题是，当我通过 DeleteEmployee 中的 catch 部分时，如何将 ModelStateErrors 发送给操作 Employee

   public ActionResult Employee(int ID, string Name)
    {
        EmployeeListModel model = new EmployeeListModel (ID, projectName);
        return View(model);
    }

 public ActionResult DeleteEmployee(Employee emp)
    {

        try
        {
            emp.Delete();
            return RedirectToAction("Employee", new { ID = emp.ID, Name = emp.Name });
        }

        catch (Exception e)
        {
            EmployeeListModel model = new EmployeeListModel (emp.ID, emp.Name);
            ModelState.AddModelError("Error", e.Message);
            return RedirectToAction("Employee", model);
        }
    }

---

With return View("Employee", model);我仍然无法将 ID 和名称作为参数发送。

Answer 1

使用TempData 将ModelState 持久化到多个控制器操作中。

MvcContrib 有一个执行此操作的操作过滤器。 Jeremy Skinner 在http://www.jeremyskinner.co.uk/2008/10/18/storing-modelstate-in-tempdata-with-aspnet-mvc/ 上写了代码和一篇关于它的博客文章。那里的源链接已损坏，所以我在下面发布了代码。

ModelStateToTempDataAttribute Source Code

/// <summary>
/// When a RedirectToRouteResult is returned from an action, anything in the ViewData.ModelState dictionary will be copied into TempData.
/// When a ViewResultBase is returned from an action, any ModelState entries that were previously copied to TempData will be copied back to the ModelState dictionary.
/// </summary>
public class ModelStateToTempDataAttribute : ActionFilterAttribute
{
    public const string TempDataKey = "__MvcContrib_ValidationFailures__";

    /// <summary>
    /// When a RedirectToRouteResult is returned from an action, anything in the ViewData.ModelState dictionary will be copied into TempData.
    /// When a ViewResultBase is returned from an action, any ModelState entries that were previously copied to TempData will be copied back to the ModelState dictionary.
    /// </summary>
    /// <param name="filterContext"></param>
    public override void OnActionExecuted(ActionExecutedContext filterContext)
    {
        var modelState = filterContext.Controller.ViewData.ModelState;

        var controller = filterContext.Controller;

        if(filterContext.Result is ViewResultBase)
        {
            //If there are failures in tempdata, copy them to the modelstate
            CopyTempDataToModelState(controller.ViewData.ModelState, controller.TempData);
            return;
        }

        //If we're redirecting and there are errors, put them in tempdata instead (so they can later be copied back to modelstate)
        if((filterContext.Result is RedirectToRouteResult || filterContext.Result is RedirectResult) && !modelState.IsValid)
        {
            CopyModelStateToTempData(controller.ViewData.ModelState, controller.TempData);
        }
    }

    private void CopyTempDataToModelState(ModelStateDictionary modelState, TempDataDictionary tempData)
    {
        if(!tempData.ContainsKey(TempDataKey)) return;

        var fromTempData = tempData[TempDataKey] as ModelStateDictionary;
        if(fromTempData == null) return;

        foreach(var pair in fromTempData)
        {
            if (modelState.ContainsKey(pair.Key))
            {
                modelState[pair.Key].Value = pair.Value.Value;

                foreach(var error in pair.Value.Errors)
                {
                    modelState[pair.Key].Errors.Add(error);
                }
            }
            else
            {
                modelState.Add(pair.Key, pair.Value);
            }
        }
    }

    private static void CopyModelStateToTempData(ModelStateDictionary modelState, TempDataDictionary tempData)
    {
        tempData[TempDataKey] = modelState;
    }
}

这里有一些类似的帖子

• ASP.NET MVC - How to Preserve ModelState Errors Across RedirectToAction?
• How can I maintain ModelState with RedirectToAction?

Answer 2

从视图来看，模型状态字典是 ViewDataDictionary 的一部分，因此请尝试通过 viewdata 访问它，至少在 MVC 3 中是这样（相信在旧版本中也是如此）。您不需要通过模型传递它，而是通过这种方式访问​​它。

但是，我不知道如果您进行重定向，模型状态错误是否会保留；您可能想直接返回响应：

return View("Employee", model);

HTH。

Answer 3

ID 和 Name 的值被封装在您传递给“View”ActionResult 的 EmployeeListModel 中：

• 型号.ID
• 型号.名称

注意，@Brian 是正确的，因为您需要使用“View”ActionResult 而不是“RedirectToAction”ActionResult，否则模型状态错误将会丢失。另一种方法是将模型状态存储在 TempData 中，它实际上是会话对象的特殊包装器。如果您需要确保正确更新您的网址，则需要使用“RedirectToAction”ActionResult 之类的东西...

Answer 4

将 ModelState 存储在 TempData 中：

TempData["ModelState"] = ModelState;

然后使用动作过滤器合并 ModelState，例如：

protected override void OnActionExecuted(ActionExecutedContext context)
{
    filterContext.Controller.ViewData.ModelState.Merge((ModelStateDictionary)TempData["ModelState"]);
}

希望这会有所帮助。

Answer 5

试试下面的代码 //作为最佳实践，始终使用 Viewmodel，例如employeeViewMode 并将您的视图强输入到 viewmodel 公共类 EmployeviewModel { 公共 int id； 公共字符串名称； 公共字符串错误消息； } 公共 ActionResult Employee(int ID) { EmployeeListModel model = new EmployeeListModel(ID, projectName); EmployeviewModel vm = new EmployeviewModel(); vm.id = 模型.id; vm.name = 型号.name; if (TempData.Keys.Count() > 0) { vm.errormessage = TempData["errormessage"]; } 返回视图（vm）； }

    public ActionResult DeleteEmployee(Employee emp)
    {
        try
        {
            emp.Delete();
            return RedirectToAction("Employee", new { ID = emp.ID, Name = emp.Name });
        }

        catch (Exception e)
        {
            //use TempData to store error message
            TempData["ErrorMessage"] = e.message;
            return RedirectToAction("Employee", emp.ID);
        }
    }