Question

我正在尝试通过MVC3上传文件这是我的观点：

@{
    ViewBag.Title = "Pic";
    Layout = "~/Areas/Admin/Views/Shared/_AdminLayout.cshtml";
}

@using (Html.BeginForm("FileUpload", "Blog", FormMethod.Post))
{
    <input name="uploadFile" type="file" />
    <input type="submit" value="Upload File" />
}

这是我的行动：

public ActionResult FileUpload()
        {
            return View();
        }

        [AcceptVerbs(HttpVerbs.Post)]
        public ActionResult FileUpload(HttpPostedFileBase uploadFile)
        {
            if (uploadFile.ContentLength > 0)
            {
                string filePath = Path.Combine(HttpContext.Server.MapPath("../Uploads"),
                                               Path.GetFileName(uploadFile.FileName));
                uploadFile.SaveAs(filePath);
            }
            return View();
        }

我的代码出了什么问题？我有这个错误

Object reference not set to an instance of an object.

在这一行

 if (uploadFile.ContentLength > 0)

Answer 1

您应该在表单中添加enctype属性。

@using (Html.BeginForm("FileUpload", "Blog", FormMethod.Post,
                       new { enctype = "multipart/form-data" }))

Answer 2

将new { enctype = "multipart/form-data" }作为参数添加到表单中，您就可以开始了。它看起来像：

@using (Html.BeginForm("FileUpload", "Blog", FormMethod.Post, 
                       new { enctype = "multipart/form-data" }))

不要检查存在控件的文件大小。我建议控制它是否在控制器端为空。

Answer 3

替换

@using (Html.BeginForm("FileUpload", "Blog", FormMethod.Post))

带

@using (Html.BeginForm("FileUpload", "Blog", FormMethod.Post, new { enctype="multipart/form-data"}))

要详细了解enctype =“multipart / form-data”的含义，请参阅here

通过MVC3上传文件

3 个答案: