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通过Ajax上传的文件未在MVC中的请求中附加文件

ajax

我有一个简单的表单,其中包含类型文件的输入,该文件仅接受图像。我只想发布文件,将其保存在表以及服务器中。

下面是我的cshtml

@using (Html.BeginForm("UploadSlider", "Admin", FormMethod.Post, new { id = "frmUploadSliderImage", @class = "form-admin" }))
{
     <h2 class="form-login-heading">upload images</h2>
     <div class="login-wrap">
     <span class="btn btn-default btn-file">
     Browse <input type="file" id="sliderFile" multiple="multiple">
     </span>&nbsp;
     <span class="text-muted" id="filePlaceHolder">No files selected</span>
     <span class="text-danger"></span>
     <button class="btn btn-theme btn-block" name="upload" onclick="javascript: ValidateSliderImageandPost('frmUploadSliderImage', this);" id="btnUploadSliderImage" type="submit"><i class="fa fa-upload"></i> UPLOAD</button>
     </div>
}

这是我的js ajax部分

function ValidateSliderImageandPost(form, ctrl) {
    $("#" + form).on("submit", function (e) {
        e.preventDefault();
        var formContainer = $('#' + form + ' .text-danger');
        var formdata = new FormData();
        var fileInput = $('#sliderFile');
        if ($(fileInput).get(0).files.length == 0)
        {
            $('.btn-file :file').parent().siblings().filter(".text-danger").html('Please select a file!');
        }
        if ($(formContainer).text().length == 0) {
            run_waitMe('Uploading! Please wait...', 'stretch', '.container');
            $.each($(fileInput).get(0).files, function (index,value) {
                formdata.append($(this).attr('name'), $(this));
            });
            postData('UploadSlider', formdata, '.upslider .status');
            if (msg) {
                $(".container").find('#cont').waitMe('hide');
                $("#" + form).find('input[type=text], textarea').val('').removeClass("alert-success");
            }
            else {
                $(".container").find('#cont').waitMe('hide');
                $("#" + form).find('input[type=text], textarea').removeClass("alert-success");
            }

        }
        $("#" + form).unbind('submit');
        return false;
    });
}

function postData(url,data,target)
{
$.ajax({
    url: url,
    type: "POST",
    dataType: 'json',
    data: data,
    processData: false,
    contentType:false,
    success: function (data) {
        if (data.result) {
            animateStatus("success", data.message, target);
            msg = true;
        }
        else {
            animateStatus("fail", data.message, target);
            msg = false;
        }
    },
    error:
        function (data) {
            animateStatus("fail", data.message, target);
            msg = false;
        }
});
}

这是我的控制器部分

[HttpPost]
        public JsonResult UploadSlider()
        {
            bool valid = false;
            bool val = false;
            if (Request.Files.Count > 0)
            {
                valid = true;
            }
            else
            {
                return Json(new { result = false, message = "Something went wrong! Please try again!" });
            }
            if (valid)
            {
                List<string> fil = new List<string>();
                foreach (HttpPostedFileBase f in Request.Files)
                {
                    HttpPostedFileBase file = f; //Uploaded file
                    string fileName = file.FileName;
                    fil.Add("./Images/Galllery/" + fileName);
                    System.IO.Stream fileContent = file.InputStream;
                    file.SaveAs(Server.MapPath("~/Images/Gallery/") + fileName);
                }
                using (var context = new MCBConnectionString())
                {
                    foreach (string path in fil)
                    {
                        tbl_slider slider = new tbl_slider();
                        slider.slurl = path;
                        slider.slalt = "";
                        context.tbl_slider.Add(slider);
                        context.SaveChanges();
                        val = true;
                    }
                }
                if (val)
                {
                    return Json(new { result = true, message = "Uploaded video successfully." });
                }
                else
                {
                    return Json(new { result = false, message = "Could not upload video. Please try again!" });
                }
            }
            return Json(new { result = false, message = "Could not upload video. Please try again!" });


        }

当我调试并检查Request.Files.Count时,它将始终为零。是否有其他解决方法,或者我在发布文件时犯了任何错误。我已遵循

链接,并根据需要进行了更改。


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2020-07-26

共1个答案

小编典典

代替:

$.each($(fileInput).get(0).files, function (index, value) {
    formdata.append($(this).attr('name'), $(this));
});

您可以使用:

$.each($(fileInput).get(0).files, function (index, value) {
    formdata.append(value.name, value);
});

主要区别在于,使用您的方法,Content-Disposition部分不包含filename,因此ASP.NET无法将其识别为文件内容:

------WebKitFormBoundaryZxwCwBC0O8Q3hOAO
Content-Disposition: form-data; name="foo.png"

[object Object]
------WebKitFormBoundaryZxwCwBC0O8Q3hOAO
Content-Disposition: form-data; name="bar.png"

[object Object]
------WebKitFormBoundaryZxwCwBC0O8Q3hOAO--

用我的方法,请求将如下所示:

------WebKitFormBoundary1ERBVX0wzdVczcR0
Content-Disposition: form-data; name="foo.png"; filename="foo.png"
Content-Type: imag/png

[object Object]
------WebKitFormBoundary1ERBVX0wzdVczcR0
Content-Disposition: form-data; name="bar.png"; filename="bar.png"
Content-Type: image/png

[object Object]
------WebKitFormBoundary1ERBVX0wzdVczcR0--

现在您可以看到实际的差异。在第一种情况下,您将没有文件filenameContent- Type文件,ASP.NET只会将这些元素视为标准表单发布的数据,而不是文件。

另外,不要使用实际的文件名,name而是可以考虑将其替换为一些通用的文件名:

$.each($(fileInput).get(0).files, function (index, value) {
    formdata.append('sliderFiles', value);
});

现在,您可以通过采用List<HttpPostedFileBase>参数而不是使用来进一步改善控制器操作Request.Files

[HttpPost]
public ActionResult UploadSlider(List<HttpPostedFileBase> sliderFiles)
{
    ...
}

关于您的代码的另一句话是,HTML5
FormData在订购浏览器中不可用,并且您的代码将自动失败。如果您需要支持较旧的浏览器,则可能需要通过测试浏览器的功能来执行渐进式增强,如果浏览器不支持FormData,则退回到标准表格POST:

$("#" + form).on("submit", function (e) {
    if(window.FormData === undefined) {
        // The browser doesn't support uploading files with AJAX
        // falling back to standard form upload
    } else {
        // The browser supports uploading files with AJAX =>
        // we prevent the default form POST and use AJAX instead
        e.preventDefault();

        ...
    }
});
2020-07-26