Question

我已经连续两个小时了，我一直在讨价还价。

我收到此错误：

值不能为null或为空。参数名称：contentPath

在我看来的这一行：

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

下面给出的堆栈跟踪似乎表明已经调用Url.Content，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（）in   MyProject的\查看\杂志\ 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   controllerContext，ActionResult actionResult）+13
  System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive（IList的1 filters, Int32 filterIndex, ResultExecutingContext preContext, ControllerContext controllerContext, ActionResult actionResult) +56 System.Web.Mvc.ControllerActionInvoker.InvokeActionResultFilterRecursive(IList 1   filters，Int32 filterIndex，ResultExecutingContext preContext，   ControllerContext controllerContext，ActionResult actionResult）+420
  System.Web.Mvc.ControllerActionInvoker.InvokeActionResultWithFilters（ControllerContext   controllerContext，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.CallEndDelegate（IAsyncResult   asyncResult）+10
  System.Web.Mvc.Async.WrappedAsyncResultBase 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.CallEndDelegate（IAsyncResult的   asyncResult）+29
  System.Web.Mvc.Async.WrappedAsyncResultBase 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.CallEndDelegate（IAsyncResult的   asyncResult）+22
  System.Web.Mvc.Async.WrappedAsyncResultBase 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 1.CallEndDelegate（IAsyncResult的   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）   结果）+9
  System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute（）   +9644097 System.Web.HttpApplication.ExecuteStep（IExecutionStep step，Boolean＆amp; completedSynchronously）+155

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，而且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。只有当ModelState在回发后有错误时才会引发它。

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

神圣的废话！

如果你曾经遇到过这个错误，请记住，只有一个，而且只有一个导致此错误。

您视图中的行网络中的某个位置已传递null @ Url.Content方法的值。周期。

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。： - ）

这就是我如何找到解决方案并缓解我的痛苦。

＆＃34;值不能为null或为空。参数名称：contentPath＆＃34;当ModelState出错时，在回发上最意外的一行

1 个答案: