Mvc c#上传pdf，有错误消息(HTTP 404)，但文件已经上传到指定的路径

我想用c#写Mvc上传pdf，但是有一些困难。当我上传文件时，有错误消息(HTTP 404)，但是文件已经上传到指定的路径。我怎么解它?谢谢。

错误信息:

• 在'/'中出现服务器错误。
• 资源未找到。描述:HTTP 404。你是一个资源查找(或一个依赖)可能已删除的名称有更改，或暂时不可用。
• 请查看以下URL，并确保拼写正确正确。URL请求:/MakeUpExam/Upload

代码:

控制器:

  public ActionResult MakeUpExam()
    {
        List<TesrModel> TesrModel = new List<TesrModel>();
            using (SqlConnection Coon = new SqlConnection(connStr))
            {
                Coon.Open();
                SqlCommand commandExamInfo = new SqlCommand();
                using (commandExamInfo = new SqlCommand(@"select * from aaa where bbb=@bbb", Coon)) commandExamInfo.Parameters.Add(new SqlParameter("@bbb", "123"));
                {
                    commandExamInfo.CommandType = CommandType.Text;
                    SqlDataReader reader;
                    reader = commandExamInfo.ExecuteReader();
                    {
                        if (reader.FieldCount != 0)
                        {
                            while (reader.Read())
                            {
                                TesrModel.Add(
                                  new TesrModel()
                                  {
                                      a = reader["a"].ToString(),
                                      b = reader["b"].ToString(),
                                      c = reader["c"].ToString(),
                                  });
                            }
                        }
                    }
            }
        }
        return View(TesrModel);
    }

    [HttpPost]
    public ActionResult Upload(HttpPostedFileBase file)
    {
        using (SqlConnection Coon = new SqlConnection(connStr))
        {
            SqlCommand command = new SqlCommand();
            Coon.Open();
            using (command = new SqlCommand(@"select ccc from ddd where eee=@eee and fff= @fff", Coon))
                command.Parameters.Add(new SqlParameter("@eee", "aaa"));
            command.Parameters.Add(new SqlParameter("@fff", "bbb"));
            {
                if (file != null)
                {
                    if (file.ContentLength <= 1042880)
                    {
                        if (file.ContentType == "pdf" || file.ContentType== "application/pdf")
                        {
                            var fileName = Path.GetFileName(file.FileName);
                            var Newfilename = fileName + "_" + DateTime.Now.ToString();
                            var path = Path.Combine(@"D:'data", Newfilename);
                            file.SaveAs(path);
                        }
                        else
                        {
                            ViewBag.Message  = "msut pdf file";
                        }
                    }
                    else
                    {
                        ViewBag.Message = "file too large";
                    }
                }
                else
                {
                    ViewBag.Message = "please select file, thanks.";
                }
            }
        }
        return RedirectToAction("Upload");
    }
}}

视图

@model IEnumerable<MakeUpExam.Models.TesrModel>
<h2>Upload</h2>
<table class="table" border="1">
    <tr>
        <th>
            @Html.DisplayNameFor(model => model.a)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.b)
        </th>
        <th>
            @Html.DisplayNameFor(model => model.c)
        </th>
        <th>
            upload file
        </th>
        <th>
            upload  time
        </th>
    </tr>
    @foreach (var item in Model)
    {
    <tr>
        <td>
            @Html.DisplayFor(modelItem => item.a)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.b)
        </td>
        <td>
            @Html.DisplayFor(modelItem => item.c)
        </td>
        <td>
            <form action="@Url.Action("Upload")" method="post" enctype="multipart/form-data">
                <label for="file">Filename:</label>
                <input type="file" name="file" id="file" /><input type="submit" value="upload file" />
            </form>
        </td>
        <td>
        </td>
    </tr>
    }
</table>

模型

public class testModel
{
    public string a{ get; set; }
    public string b{ get; set; }
    public string c{ get; set; }
}