Ajax.ActionLink 找不到公共控制器方法，因为它是异步的

Question

我认为有以下 AjaxActionLink 代码：

@Ajax.ActionLink("Download", "DownloadDocument", "Document", new { Model.DocumentNumber, Model.DocumentName, TypeVisualization = TypeVisualization.Attachment }, new AjaxOptions { HttpMethod = "Post", UpdateTargetId = "modal-container", LoadingElementId = "ajaxLoading" }, new { @class = "modal-link" })

然后，在我的 DocumentController 中：

        [HttpPost]
        public async Task<ActionResult> DownloadDocument(DownloadFileRequest request)
        {
            DownloadFileCommand command = new DownloadFileCommand();
            Mapper.Map(UserModel, command);
            Mapper.Map(request, command);
            var result = await documentRepository.DownloadDocument(command);
            ContentDisposition cd = new ContentDisposition
            {
                FileName = Server.UrlPathEncode(result.DocumentName),
                Inline = request.TypeVisualization == TypeVisualization.Inline
            };
            return new FileContentResultWithContentDisposition(result.Content, result.MimeType, cd);
        }

方法被命中，但返回后，没有文件发送到浏览器并抛出异常：

System.Web.HttpException (0x80004005): A public action method 'DownloadDocument' was not found on controller Document
   en System.Web.Mvc.Controller.HandleUnknownAction(String actionName)
   en System.Web.Mvc.Controller.<BeginExecuteCore>b__1d(IAsyncResult asyncResult, ExecuteCoreState innerState)
   en System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult)
   en System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
   en System.Web.Mvc.Controller.EndExecuteCore(IAsyncResult asyncResult)
   en System.Web.Mvc.Controller.<BeginExecute>b__15(IAsyncResult asyncResult, Controller controller)
   en System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult)
   en System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
   en System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult)
   en System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult)
   en System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState)
   en System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncVoid`1.CallEndDelegate(IAsyncResult asyncResult)
   en System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResultBase`1.End()
   en System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult)
   en System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result)
   en System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
   en System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)

这里发生了什么？

Answer 1

我建议您不要使用 AJAX 下载文件。即使调用成功，您对成功回调中的二进制内容也无能为力，并且无法将其保存到客户端计算机。例如，在您的 AjaxLink 中，您似乎指定了 UpdateTargetId = "modal-container" 参数，但我想知道如果您的控制器操作返回二进制流，您希望在此 div 中发生什么。

您可以使用 HTML 表单：

@using (Html.BeginForm("DownloadDocument", "Document", FormMethod.Post))
{
    @Html.HiddenFor(x => x.DocumentNumber)
    @Html.HiddenFor(x => x.DocumentName)
    @Html.Hidden("TypeVisualization", TypeVisualization.Attachment)
    <input type="submit" class="modal-link">Download</input>
}

现在就您的错误而言，我怀疑它与操作是async 的事实有关。这应该开箱即用。确保将操作正确放置在 DocumentController 中：

public class DocumentController: Controller
{
    ...
}