上传文件到服务器

                <table class="table table-strippled exhibit-table">
                    <tbody>
                        <tr>
                            <td class="background-title"><i class="red-font"></i><span class="background-title"> 备份文件</span></td>
                            <td>
                                <form action="#" class="clearfix" id="uploadForm" method="post">
                                    <input id="bkImg" type='file' name="files"
                                           class="file" data-min-file-count="2" onchange="FileChange('bkImg', 'uploadForm')">
                                </form>
                            </td>

                        </tr>
                    </tbody>
                </table>

//图片上传
var nameImg = "";//定义全局变量存储文件名
function FileChange(inputId, uploadForm) {
    if ($("#" + inputId).val() == "") {
        return;
    }
    else {
        var formData = new FormData($("#" + uploadForm)[0]);
        $.ajax({
            url: "/CContractMgr/SubmitImg",
            type: "POST",
            data: formData,
            async: false,
            cache: false,
            contentType: false,
            processData: false,
            success: function (result) {
                if (result.r > 0) {
                    nameImg = result.nameImg;//获取返回的文件名
                } else {
                    if (result.message.trim() == "") { result.message = "系统错误,请重新操作!"; }
                    layer.alert(result.message);
                    $("#" + inputId).val("");
                }
            }
        });
    }
}

        /// <summary>
        /// 上传图片
        /// </summary>
        /// <returns></returns>
        [HttpPost]
        public JsonResult SubmitImg()
        {
            var _r = 0;
            var _message = "";
            var _nameImg = "";
            //上传和返回(保存到数据库中)的路径
            string uppath = string.Empty;
            string savepath = string.Empty;
            HttpPostedFileBase imgFile = Request.Files[0];
            if (Request.Files.Count > 0)
            {

                if (imgFile != null)
                {
                    //创建图片新的名称
                    string nameImg = DateTime.Now.ToString("yyyyMMddHHmmssfff");
                    //获得上传图片的路径
                    string strPath = imgFile.FileName;
                    //获得上传图片的类型(后缀名)
                    string type = strPath.Substring(strPath.LastIndexOf(".") + 1).ToLower();
                    if (ValidateImg(type))
                    {
                        //拼写上传图片的路径
                        var ImgUrl = "/Images/contract/contractImg/";
                        uppath = Server.MapPath(ImgUrl);
                        if (!Directory.Exists(uppath))//判断上传文件夹是否存在，若不存在，则创建
                        {
                            Directory.CreateDirectory(uppath);//创建文件夹
                        }
                        uppath += nameImg + "." + type;//图片保存路径

                        //拼写数据库保存的相对路径字符串
                        savepath += ImgUrl + nameImg + "." + type;

                        //上传图片
                        try
                        {
                            imgFile.SaveAs(uppath);
                            _r = 1;
                            _message = "上传成功";
                            _nameImg = nameImg;
                        }
                        catch (Exception ex)
                        {
                            UtilityHelp.WriteLog(ex, ex.Message);
                            _r = 0;
                            _message = "上传异常!";
                        }
                    }
                    else
                    {
                        _r = 0;
                        _message = "合同备份仅支持PDF格式，请加密后重新上传!";
                    }
                }
            }
            var json = new { r = _r, filename = savepath, message = _message, nameImg = _nameImg };
            return Json(json, JsonRequestBehavior.AllowGet);
        }

        /// <summary>
        /// 图片上传类型
        /// </summary>
        /// <param name="imgName"></param>
        /// <returns></returns>
        public bool ValidateImg(string imgName)
        {
            string[] imgType = new string[] { "pdf" };

            int i = 0;
            bool blean = false;
            string message = string.Empty;

            //判断是否为Image类型文件
            while (i < imgType.Length)
            {
                if (imgName.Equals(imgType[i].ToString()))
                {
                    blean = true;
                    break;
                }
                else if (i == (imgType.Length - 1))
                {
                    break;
                }
                else
                {
                    i++;
                }
            }
            return blean;
        }