当ModelState有错误时,回传上最意外的行上的"值不能为null或为空.参数名称:contentPath"

Question

我已经连续两个小时跟这个怪物讨价还价了.

我收到此错误:

值不能为null或为空.参数名称:contentPath

在我看来这一行:

@Html.ValidationMessageFor(model => model.IssueName, 
  "", new { @class = "text-danger" })

下面给出的堆栈跟踪似乎表明Url.Content已经进行了调用,但我没有进行此类调用.下面是堆栈跟踪,然后是该行周围的一些代码行导致错误:

[ArgumentException:Value不能为null或为空.参数名称:contentPath] System.Web.Mvc.UrlHelper.GenerateContentUrl(String contentPath,HttpContextBase httpContext)+125
System.Web.Mvc.UrlHelper.Content(String contentPath)+26
ASP._Page_Views_Journal_EditIssue_cshtml.Execute()在MyProject\Views \中Journal\EditIssue.cshtml:45
System.Web.WebPages.WebPageBase.ExecutePageHierarchy(
)+ 197 System.Web.Mvc.WebViewPage.ExecutePageHierarchy()+ 105
System.Web.WebPages.StartPage.RunPage()+ 17
System.Web. WebPages.StartPage.ExecutePageHierarchy()+64
System.Web.WebPages.WebPageBase.ExecutePageHierarchy(WebPageContext pageContext,TextWriter writer,WebPageRenderingBase startPage)+78
System.Web.Mvc.RazorView.RenderView(ViewContext viewContext,TextWriter writer,Object instance)+ 256
System.Web.Mvc.BuildManagerCompiledView.Render(ViewContext viewContext,TextWriter writer)+107
System.Web.Mvc.ViewResultBase.ExecuteResult(ControllerContext context)+291 System.Web.Mvc.ControllerActionInvoker.InvokeActionResult(ControllerContext controllerContex t,ActionResult actionResult)+13
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList 1过滤器,Int32 filterIndex,ResultExecutingContext preContext,ControllerContext controllerContext,ActionResult actionResult)+420 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters(ControllerContext controllerContext,IList 1 .CallEndDelegate(IAsyncResult asyncResult)+10 System.Web.Mvc.Async.WrappedAsyncResultBase 1.CallEndDelegate(IAsyncResult asyncResult)+29 System.Web.Mvc.Async.WrappedAsyncResultBase 1.CallEndDelegate(IAsyncResult asyncResult)+22 System.Web.Mvc. Async.WrappedAsyncResultBase 1.CallEndDelegate(IAsyncResult asyncResult)+29 System.Web.Mvc.Async.WrappedAsyncResultBase`1.End()+ 49 System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult)+28 System.Web.Mvc. MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result)+9 System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()+9 644097 System.Web.HttpApplication.ExecuteStep(IExecutionStep step,Boolean&completedSynchronously)+1551 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +56
System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList
1 filters, ActionResult actionResult) +52
System.Web.Mvc.Async.<>c__DisplayClass2b.<BeginInvokeAction>b__1c() +173 System.Web.Mvc.Async.<>c__DisplayClass21.<BeginInvokeAction>b__1e(IAsyncResult asyncResult) +100
System.Web.Mvc.Async.WrappedAsyncResult
1.End() +49
System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeAction(IAsyncResult asyncResult) +27
System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState) +13
System.Web.Mvc.Async.WrappedAsyncVoid
1.End() +49
System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult) +36 System.Web.Mvc.Controller.<BeginExecute>b__15(IAsyncResult asyncResult, Controller controller) +12
System.Web.Mvc.Async.WrappedAsyncVoid
1.End() +49
System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +26
System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +21
System.Web.Mvc.Async.WrappedAsyncVoid

抛出异常的行周围的代码行是:

<div class="form-group">
    @Html.LabelFor(model => model.IssueName, htmlAttributes: new { @class = "control-label col-md-2"})
    <div class="col-md-10">
        @Html.EditorFor(model => model.IssueName, new { htmlAttributes = new { @class = "form-control", id = "IssueName" } })
        @Html.ValidationMessageFor(model => model.IssueName, "", new { @class = "text-danger" })
    </div>
</div>

重要

奇怪的是,只有当我从回发后回来时才会引发异常,从来没有在我第一次加载视图时,甚至在ModelState没有错误时也是如此.只有ModelState在回发后出现错误时才会引发它.

这是一些服务器端代码,但我没有看到任何可能出错的原因:

[HttpPost]
public async Task<ActionResult> EditIssue(EditIssueViewModel viewModel)
{
    viewModel.AvailableTags = BusinessManager.GetAllTags();

    if (viewModel.IssuePDFFile == null || viewModel.IssuePDFFile.ContentLength == 0)
    {
        ModelState.AddModelError("", "Please select a file to upload.");
        return View(viewModel);
    }

    var fileInfo = new FileInfo(viewModel.IssuePDFFile.FileName);
    if (!StaticData.AcceptedContentTypes.Contains(viewModel.IssuePDFFile.ContentType, StringComparer.InvariantCultureIgnoreCase) ||
        !fileInfo.Extension.Equals(".pdf", StringComparison.InvariantCultureIgnoreCase))
    {
        ModelState.AddModelError("", "You can only select a PDF file.");
        return View(viewModel);
    }

    if (!ModelState.IsValid)
    {
        var errors = ModelState.Values.SelectMany(v => v.Errors)
            .Select(e => new { e.ErrorMessage, e.Exception });

        var errorList = errors.ToList();

        errorList.ForEach(e => Debug.Print(e.ErrorMessage));
        errorList.ForEach(e => ModelState.AddModelError("", e.ErrorMessage));

        return View(viewModel);
    }

    var operationResult = await BusinessManager.EditIssueAsync(viewModel);

    if (!operationResult.Succeeded)
    {
        ModelState.AddModelError("", operationResult.FailureMessage);
        return View(viewModel);
    }

    viewModel = (EditIssueViewModel)BusinessManager.GetIssueWithRelationships(viewModel.IssueId);
    viewModel.SuccessMessage = operationResult.SuccessMessage;
    return View(viewModel);
}

Answer 1

哇靠!

如果您曾经有过这样的错误,请记住,只有一个,而且只有一个导致此错误.

在视图的行网络中的某个位置,您已将空值传递给@ Url.Content方法.期.

它报告异常的行可能与异常无关,可能距离罪魁祸首一两英里.

搜索,搜索,搜索疯狂.:-)

这就是我找到解决方案的方法,并减轻了我的痛苦.