Question

我正在编写C＃ASP.Net MVC应用程序，以便客户端将文件发布到其他服务器。我使用通用处理程序来处理从客户端到服务器的已发布文件。但是在我的处理程序中，System.Web.HttpContext.Current.Request.Files总是为空（0计数）。

表格代码：

@model ITDB102.Models.UploadFileResultsModels
@{
    Layout = "~/Views/Shared/_Layout.cshtml";
}

<div>
    <h1>Upload File</h1>
    <form id="file-form" action="/Files/UploadFile" method="post" data-ajax="false" enctype="multipart/form-data">
        <div><input type="file" id="FilePath" name="FilePath"/>
        <button type="submit">Send File</button></div>
    </form>
</div>

@section scripts{
    <script src="~/Scripts/jquery-1.10.2.js"></script>
    <script type="text/javascript">

        // Variable to store your files
        var files;
        var form = document.getElementById('file-form');

        // Add events
        $('input[type=file]').on('change', prepareUpload);

        // Grab the files and set them to our variable
        function prepareUpload(event) {
            files = $('#FilePath').get(0).files;
        }

        form.onsubmit = function (event) {
            uploadFiles(event);
        }

        // Catch the form submit and upload the files
        function uploadFiles(event) {
            event.stopPropagation(); // Stop stuff happening
            event.preventDefault(); // Totally stop stuff happening           

            // Create a formdata object and add the files
            var data = new FormData();
            if (files.lenght > 0)
            {
                data.append('UploadedFiles', files[0], file[0].name);
            }

            //setup request
            var xhr = new XMLHttpRequest();
            //open connection
            xhr.open('POST', '/Files/UploadFile',false);
            xhr.setRequestHeader("Content-Type", files.type);
            //send request
            xhr.send(data);

        }

    </script>

}

处理程序：

/// <summary>
    /// Uploads the file.
    /// </summary>
    /// <returns></returns>
    [HttpPost]
    public virtual ActionResult UploadFile()
    {
        HttpPostedFile myFile = System.Web.HttpContext.Current.Request.Files["UploadedFiles"];

        bool isUploaded = false;
        string message = "File upload failed";

        if (myFile != null && myFile.ContentLength != 0)
        {
            string pathForSaving = Server.MapPath("~/Uploads");
            if (this.CreateFolderIfNeeded(pathForSaving))
            {
                try
                {
                    myFile.SaveAs(Path.Combine(pathForSaving, myFile.FileName));
                    isUploaded = true;
                    message = "File uploaded successfully!";
                }
                catch (Exception ex)
                {
                    message = string.Format("File upload failed: {0}", ex.Message);
                }
            }
        }
        return Json(new { isUploaded = isUploaded, message = message }, "text/html");
    }


    #region Private Methods

    /// <summary>
    /// Creates the folder if needed.
    /// </summary>
    /// <param name="path">The path.</param>
    /// <returns></returns>
    private bool CreateFolderIfNeeded(string path)
    {
        bool result = true;
        if (!Directory.Exists(path))
        {
            try
            {
                Directory.CreateDirectory(path);
            }
            catch (Exception)
            {
                /*TODO: You must process this exception.*/
                result = false;
            }
        }
        return result;
    }

    #endregion

请帮帮我。感谢。

Answer 1

最后，我发现了问题。

我的控制器中的代码var myFile = System.Web.HttpContext.Current.Request.Files["UploadedFiles"];由于某种原因永远不会起作用。我的ajax没有任何问题。我在控制器中更改了我的代码，现在它正在查找。

[HttpPost]
    public virtual ActionResult UploadFile()
    {
        //var myFile = System.Web.HttpContext.Current.Request.Files["UploadedFiles"];
        //
        bool isUploaded = false;
        string message = "File upload failed";

        for (int i = 0; i < Request.Files.Count; i++ )
        {
            var myFile = Request.Files[i];

            if (myFile != null && myFile.ContentLength != 0)
            {
                string pathForSaving = Server.MapPath("~/Uploads");
                if (this.CreateFolderIfNeeded(pathForSaving))
                {
                    try
                    {
                        myFile.SaveAs(Path.Combine(pathForSaving, myFile.FileName));
                        isUploaded = true;
                        message = "File uploaded successfully!";
                    }
                    catch (Exception ex)
                    {
                        message = string.Format("File upload failed: {0}", ex.Message);
                    }
                }
            }

        }


        return Json(new { isUploaded = isUploaded, message = message }, "text/html");
    }

    #endregion

    #region Private Methods

    /// <summary>
    /// Creates the folder if needed.
    /// </summary>
    /// <param name="path">The path.</param>
    /// <returns></returns>
    private bool CreateFolderIfNeeded(string path)
    {
        bool result = true;
        if (!Directory.Exists(path))
        {
            try
            {
                Directory.CreateDirectory(path);
            }
            catch (Exception)
            {
                /*TODO: You must process this exception.*/
                result = false;
            }
        }
        return result;
    }

    #endregion

}

Answer 2

您需要为xhr设置以下内容。

dataType: 'json',
contentType: false,
processData: false,

请参阅帮助链接 - File upload using MVC 4 with Ajax

我看到，您已添加jquery库并使用了jquery选择器，那么为什么不使用$.ajax POST请求？如果您对jquery方式感兴趣，请参阅以下脚本。

$.ajax({
  type: "POST",
  url: '/Files/UploadFile',
  data: data,
  dataType: 'json',
  contentType: false,
  processData: false,
  success: function(response) {
    alert('succes!!');
  },
  error: function(param1,param2,param3) {
    alert("errror");
  }
});

Answer 3

要发布文件，发布数据必须采用multipart / form-data编码类型。因此，您必须设置请求标头，如下所示：

xhr.setRequestHeader（ “内容类型”， “多部分/格式数据”）;

请参阅示例：Upload File With Ajax XmlHttpRequest

Request.Files始终为null

3 个答案: