Question

我有一个删除对象的方法。删除不属于视图，并且是“EditReport”中的“删除”按钮。成功删除“报告”上的重定向后。

[HttpPost]
[Route("{reportId:int}")]
[ValidateAntiForgeryToken]
public async Task<IActionResult> DeleteReport(int reportId)
{
    var success = await _reportService.DeleteReportControlAsync(reportId);
    if (success == false)
    {
        ModelState.AddModelError("Error", "Messages");
        return RedirectToAction("EditReport");
    }
    ModelState.AddModelError("OK", "Messages");
    return RedirectToAction("Report");
}

在ASP.NET Core 1.0（完整.NET Framework）中，我使用以下属性在方法之间保存ModelState。我从这里开始：https://stackoverflow.com/a/35987804/3878213

我最近改用了控制器，服务和存储库的异步方法。在我看来，行动的属性也应该是异步的。最初，我重写了代码属性如下：

public class SetTempDataModelStateAttribute : Attribute, IAsyncActionFilter
    {
        public async Task OnActionExecutionAsync(ActionExecutingContext filterContext, ActionExecutionDelegate next)
        {    
            var controller = filterContext.Controller as Controller;
            var modelState = controller?.ViewData.ModelState;
            if (modelState != null)
            {
                var listError = modelState.ToDictionary(m => m.Key, m => m.Value.Errors
                    .Select(s => s.ErrorMessage)
                    .FirstOrDefault(s => s != null));
                var listErrorJson = await Task.Run(() => JsonConvert.SerializeObject(listError));
                controller.TempData["ModelState"] = listErrorJson;
            }
            await next();
        }
    }
public class RestoreModelStateFromTempDataAttribute : Attribute, IAsyncActionFilter
{
    public async Task OnActionExecutionAsync(ActionExecutingContext filterContext, ActionExecutionDelegate next)
    {
        var controller = filterContext.Controller as Controller;
        var tempData = controller?.TempData?.Keys;
        if (controller != null && tempData != null)
        {
            if (tempData.Contains("ModelState"))
            {
                var modelStateString = controller.TempData["ModelState"].ToString();
                var listError = await Task.Run(() => 
                    JsonConvert.DeserializeObject<Dictionary<string, string>>(modelStateString));
                var modelState = new ModelStateDictionary();
                foreach (var item in listError)
                {
                    modelState.AddModelError(item.Key, item.Value ?? "");
                }

                controller.ViewData.ModelState.Merge(modelState);
            }
        }
        await next();
    }
}

这对我来说似乎合乎逻辑。但是这段代码不能像我预期的那样工作。但是以下异步属性正常工作：

public class SetTempDataModelStateAttribute : ActionFilterAttribute
    {
        public override async Task OnActionExecutionAsync(ActionExecutingContext filterContext, ActionExecutionDelegate next)
        {
            await base.OnActionExecutionAsync(filterContext, next);

            var controller = filterContext.Controller as Controller;
            var modelState = controller?.ViewData.ModelState;
            if (modelState != null)
            {
                var listError = modelState.ToDictionary(m => m.Key, m => m.Value.Errors
                    .Select(s => s.ErrorMessage)
                    .FirstOrDefault(s => s != null));
                var listErrorJson = await Task.Run(() => JsonConvert.SerializeObject(listError));
                controller.TempData["ModelState"] = listErrorJson;
            }
            await next();
        }
    }
public class RestoreModelStateFromTempDataAttribute : ActionFilterAttribute
    {
        public override async Task OnActionExecutionAsync(ActionExecutingContext filterContext, ActionExecutionDelegate next)
        {
            await base.OnActionExecutionAsync(filterContext, next);

            var controller = filterContext.Controller as Controller;
            var tempData = controller?.TempData?.Keys;
            if (controller != null && tempData != null)
            {
                if (tempData.Contains("ModelState"))
                {
                    var modelStateString = controller.TempData["ModelState"].ToString();
                    var listError = await Task.Run(() => 
                        JsonConvert.DeserializeObject<Dictionary<string, string>>(modelStateString));
                    var modelState = new ModelStateDictionary();
                    foreach (var item in listError)
                    {
                        modelState.AddModelError(item.Key, item.Value ?? "");
                    }

                    controller.ViewData.ModelState.Merge(modelState);
                }
            }
            await next();
        }
    }

请告诉我哪两个选项更正确？为什么第一种选择不起作用？

Answer 1

请告诉我两个选项中哪一个更正确。

选项二更正确，因为它确实有效 - 正如您所注意到的那样。如果您不打算继承它，他们就会成功std::map。在这种情况下使用sealed似乎是合适的。实际上，quick look @ the repo表明这实际上是一种非常常见的方法。

为什么第一个选项不起作用？

它没有调用ActionFilterAttribute调用。关键是您的自定义实现中缺少base次调用中可能存在的代码。请查看here。

在ASP.NET Core 1.0中使用ModelState与RedirectToAction异步

1 个答案: